1. If 𝑓(𝑥) = 2𝑎𝑥2 + (3 - 𝑏)𝑥 + 7 and 𝑔(𝑥) = (𝑎 - 1)𝑥2 + 2𝑏𝑥 + 7 are identical, what are the zeros of function 𝑓?
To tackle this question, first identify the two keywords in it “identical” and “roots”.
As both functions 𝑓 and 𝑔 are quadratic functions and they are identical, then the
coefficient
of 𝑥2 in 𝑓 is equivalent to the coefficient of 𝑥2 in 𝑔, and the
coefficient of 𝑥 in 𝑓 is
equivalent to the coefficient of 𝑥 in 𝑔, and the constant in 𝑓 is equivalent to the
constant in 𝑔.
In other terms, if 𝑓(𝑥) = 𝑎𝑥2 + 𝑏𝑥 + 𝑐
and 𝑔(𝑥) = 𝑎'𝑥2 + 𝑏'𝑥 + 𝑐' and both functions are identical, then
𝑎 = 𝑎', 𝑏 = 𝑏', and 𝑐 = 𝑐'.
Choice D is correct – In this
question, since 𝑓 and 𝑔 are identical, then:
2𝑎 = 𝑎 - 1
Solving for 𝑎: 2𝑎 - 𝑎 = -1
𝑎 = -1
3- 𝑏 = 2𝑏
Solving for 𝑏: -𝑏 - 2𝑏 = -3
-3𝑏 = -3
𝑏 = 1
The next step after finding the values of a and 𝑏 is to replace them in 𝑓(x), and then
find the roots of 𝑓. (roots: solutions)
𝑓(𝑥) = 2(-1)𝑥2 + (3 - 1)𝑥 + 7
𝑓(𝑥) = -2𝑥2 + 2𝑥 + 7
Using the quadratic formula: 𝑥 =
-𝑏 ± √𝑏2 - 4𝑎𝑐
/
2𝑎
=
=
-2 ± √22 - 4(-2)(7)
/
2(-2)
The two solutions are 2.44 and -1.44
2. 3𝑚, 2𝑚 + 5, and 4𝑚 - 5 are three consecutive terms of a geometric sequence. If 𝑚 has a negative value, what is the value of the common ratio of this sequence?
Remember that in a geometric sequence, the ratio between any two consecutive terms is a
constant.
Choice B is correct – The three
consecutive terms are 3𝑚, 2𝑚 + 5, and 4𝑚 - 5.
Taking each two consecutive terms alone, the ratio of each is as follows:
2𝑚 + 5
/
3𝑚
and
4𝑚 - 5
/
2𝑚 + 5
. However, respecting the idea of the common ratio in a geometric sequence, we will
have both ratios equal to each other:
2𝑚 + 5
/
3𝑚
=
4𝑚 - 5
/
2𝑚 + 5
Solving for 𝑚:
(2𝑚 + 5)(2𝑚 + 5) = 3𝑚(4𝑚 - 5)
4𝑚2 + 20𝑚 + 25 = 12𝑚2 - 15𝑚
4𝑚2 + 20𝑚 - 12𝑚2 + 15𝑚 + 25 = 0
-8𝑚2 + 35𝑚 + 25 = 0
Using the quadratic formula: 𝑚 =
-𝑏 ± √𝑏2 - 4𝑎𝑐
/
2𝑎
=
-35 ± √352 - 4(-8)(25)
/
2(-8)
The two solutions for 𝑚 are: 5 and -
5
/
8
.
In the question, they stated that 𝑚 has a negative value, which means 𝑚 = 5
is rejected,
and 𝑚 = -
5
/
8
is accepted.
To find the common ratio of this sequence, simply choose one of the ratios found before
(
2𝑚 + 5
/
3𝑚
or
4𝑚 - 5
/
2𝑚 + 5) and replace 𝑚 by -
5
/
8
:
2(- 5 / 8 ) + 5 / 3(- 5 / 8 ) = 15 / 4 / - 15 / 8 = -2
3. What is the slope of the line perpendicular to the one passing through (-4, 5) and (3, 7)?
This question requires knowledge in the property of perpendicular lines in a coordinate
plane: two lines are perpendicular if the product of their slopes is equal to -1.
Choice A is correct – First step to
solve this question
is by finding the slope of the line that passes through the given points (-4, 5) and
(3, 7):
𝑚 =
𝑦2 - 𝑦1
/
𝑥2 - 𝑥1
=
7 - 5
/
3 - (-4)
=
2
/
7
Applying the property of perpendicular lines in a coordinate plane, we will have:
𝑚 ∙ 𝑚' = -1
2
/
7
∙ 𝑚' = -1
𝑚' = -1 ÷
2
/
7
then 𝑚' = -
7
/
2
4. If 𝑓(𝑥) = √𝑥 - 1 and 𝑔(𝑥) = 𝑥2, what is the domain of (𝑓 ∘ 𝑔)(𝑥)?
This question is related to composition of functions. If we have (𝑓 ∘ 𝑔)(𝑥), then we
need to substitute 𝑔(𝑥) in 𝑓(𝑥).
Choice C is correct – In this
question, 𝑔(𝑥) = 𝑥2. Therefore, we need to replace 𝑥 in 𝑓(𝑥) by
𝑥2.
This will make the function 𝑓 equals to √𝑥2 - 1
Since 𝑓 is a square root function, then to find its domain of definition,
we need to check the one and only condition regarding square roots: the radicand should
always be greater or equal to 0.
Therefore, 𝑥2 - 1 ≥ 0
𝑥2 ≥ 1
It will result: 𝑥 ≤ -1 or 𝑥 ≥ 1.
5. Using the adjacent diagram at the right, if 3tanβ = 2, what is the value of 𝑡?
This question will test your knowledge in right triangles especially using trigonometric
ratios and Pythagorean theorem.
Choice E is correct – Since
3tanβ = 2, then tanβ =
2
/
3
However, tanβ =
opposite
/
adjacent
=
ℎ
/
𝑥
Comparing both fractions, we will have
ℎ
/
𝑥
=
2
/
3
, then ℎ = 2 and 𝑥 = 3.
Using Pythagorean theorem (𝑐2 = 𝑎2 + 𝑏2):
𝑡2 = ℎ2 + 𝑥2
𝑡2 = 22 + 32
𝑡2 = 13
𝑡 = √13
6. If 𝑥 + 4𝑦 = -10 and 2𝑥 = 35 + 3𝑦, what is the value of twice the quotient of 𝑥 and 𝑦?
To solve this question, you need to combine both equations in one system of equations.
Solve for 𝑥 and 𝑦,
then answer the question regarding the value of twice the quotient of 𝑥 and 𝑦.
Choice A is correct – The system of
equations is:
{
𝑥 + 4𝑦 = -10
2𝑥 = 35 + 3𝑦
Change the second equation into 2𝑥 - 3𝑦 = 35, then multiply the
first equation by 2 to eliminate 𝑥 after subtracting both equations:
{
2𝑥 + 8𝑦 = -20
2𝑥 - 3𝑦 = 35
11𝑦 = -55
𝑦 = -
55
/
11
𝑦 = = -5
Substitute 𝑦 by -5 in one of the equations to find 𝑥:
𝑥 + 4(-5) = -10
𝑥 = 10
Twice the quotient of 𝑥 and 𝑦 means 2 (
𝑥
/
𝑦
).
Substitute 𝑥 and 𝑦 by their values:
2(
10
/
-5
) = 2(-2) = -4
7. How many 2-digit numbers are even but do not have a zero digit?
Logic and elementary number theory should be used in this question to solve it.
Choice C is correct – First of all,
they stated in the question that the numbers they
are looking for are 2-digit numbers, which means we have a range of set starting 10 till
99.
However, the numbers are even numbers and they do not contain a 0 digit.
Therefore, if we divide our set into 9
sets (10 till 19, 20 till 29, 30 till 39, 40 till 49, 50 till 59, 60 till 69,
70 till 79, 80 till 89, and 90 till 99),
we will have 4 available numbers in each set (example: 12, 14, 16, and 18).
Hence, we have 9 sets in which each has 4 available numbers. Consequently:
4 × 9 = 36
8. The length of the adjacent rectangle is equal to 14 𝑐𝑚, and the width is equal to 6 𝑐𝑚. What is the area of the shaded region? (figure is not drawn to scale)
To solve this question, do not try to use the harder method which is by trying to find the
dimensions of the shaded polygon, and then dividing it into different shapes. Rather than
doing this, find the total area of the rectangle, then subtract the area of the two
unshaded triangles.
Choice B is correct – The total
area of this rectangle can be found using
the formula 𝐴 = 𝐿 × 𝑤, with 𝐿 representing the length of the
rectangle and 𝑤
its width.
Therefore, 𝐴 = 14 × 6 = 84𝑐𝑚2.
Now, working on the triangle at the top left. Its base (b)
is equivalent to (14 - 3) which is 11 𝑐𝑚, while its
height (ℎ) is 6 - 1.5 = 4.5 𝑐𝑚.
The area of this triangle: 𝐴1 =
1
/
2
𝑏ℎ =
1
/
2
(11)(4.5) = 24.75𝑐𝑚2.
The triangle at the bottom right has a base (𝑏) equal to
14 - 1.5 = 12.5 𝑐𝑚,
and a height (ℎ) equal to 6 𝑐𝑚 (total width of the rectangle).
Its area: 𝐴2 =
1
/
2
𝑏ℎ =
1
/
2
(12.5)(6) = 37.5𝑐𝑚2.
The total area (which we already found equivalent to 84 𝑐𝑚2) is
equal to
A = 𝐴1 + 𝐴2 + 𝐴3 with
𝐴3 being the area of the shaded region.
Thus, A3 = 𝐴 - 𝐴1 - 𝐴2
= 84 -24.75 - 37.5 = 21.75 𝑐𝑚2.
9. The adjacent figure at the right shows a shape made out of a cone and a cylinder. The total volume of this shape is 39π cubic units. If the height of the cylinder is 4 units, and the radius is 3 units, what is the height of the cone?
As the shape of the figure is made out of a cone and a cylinder, then the total volume of
the given shape is the sum of the volume of the cone and the volume of the cylinder.
Choice A is correct – The volume
of the cone
is represented by 𝑉cone =
1
/
3
π𝑅2ℎ, with 𝑅 the radius of the cone and ℎ its height.
The volume of the cylinder is represented by 𝑉cylinder = π𝑅2ℎ,
with 𝑅 the radius of the cylinder and ℎ its height (= 4 units).
Since the shape is a continuous one, then the radius
of the cylinder (3 units) is equivalent to the radius of the cone.
Therefore:
𝑉Total = 𝑉cone + 𝑉cylinder
39π =
1
/
3
π(3)2ℎ + π(3)2(4)
Solving for ℎ:
39π = 3πℎ + 36π
39 = 3ℎ + 36
39 - 36 = 3ℎ
3 = 3ℎ
ℎ = 1
10. If |𝑥 - 3| = 2𝑥, which of the following is the correct value of 𝑥?
To tackle this question in the correct way, remember that an equation containing absolute
value should be separated into two parts (positive and negative components).
Choice D is correct – The equation
|𝑥 - 3| = 2𝑥 can be written as:
𝑥 - 3 = 2𝑥 or 𝑥 - 3 = -2𝑥
Solving for 𝑥 in both equations:
𝑥 - 2𝑥 = 3
-𝑥 = 3
𝑥 = -3
or: 𝑥 + 2𝑥 = 3
3𝑥 = 3
𝑥 = 1
However, checking both solutions:
If 𝑥 = -3, then |-3 - 3| = 2(-6). Consequently, |-6| = -6 which is incorrect,
therefore 𝑥 cannot be equal to -3.
If 𝑥 = 1, then |1 - 3| = 2(1). Consequently, |-2| = 2 which is correct, and
then the only solution for 𝑥 is 1.
11. During the first 4 months of this academic year, Ross passed 70% of his math assignments and 55% of his chemistry assignments, independently one of another. What is the chance that on the next attempt of each subject, he will pass the math assignment but not the chemistry?
This question requires knowledge in probability to be able to solve it.
Choice C is correct – Let us define
two events:
“𝑀: Ross passed his math assignments”, such that 𝑃(𝑀) = 0.7 as
Ross passed 70% of his math assignments, and “𝐶: Ross passed his chemistry assignments”,
such that 𝑃(𝐶) = 0.55 as Ross passed 55% of his chemistry assignments.
The complement (the outcomes in which the event does not occur) of event 𝑀 is 𝑀': Ross
didn’t pass his math assignments.
The complement of event 𝐶 is 𝐶': Ross didn’t pass his chemistry assignments.
𝑃(𝑀') = 1 - 𝑃(𝑀) = 1 - 0.7 = 0.3
𝑃(𝐶') = 1 - 𝑃(𝐶) = 1 - 0.55 = 0.45
They stated in the question that both subjects’ assignments are independent, then both
events are independent, and since we need to get the chance (probability) that on the next
attempt of each subject, he will pass the math assignment but not the chemistry, then we
are
searching for 𝑃(𝑀 and 𝐶') = 𝑃(𝑀) × 𝑃(𝐶') = 0.7 × 0.45 =
0.315
12. What is the value of 2𝑥3 if 3125 = 53𝑥 - 4 ?
To solve this question, you need first to create equivalent expressions in the equation
that have equal bases.
Choice D is correct – In 3125 =
5(3𝑥 - 4), we have 3125 = 55,
which means: 55 = 53𝑥 - 4.
Since the bases are the same, then their exponents are equivalent:
5 = 3𝑥 - 4
Solving for 𝑥:
5 + 4 = 3𝑥
3𝑥 = 9
𝑥 = 3
Substituting 𝑥 by 3 in 2𝑥3:
2(3)3 = 54
13. What is the equation of the oblique asymptote of the function 𝑓(𝑥) = 3𝑥2 - 4𝑥 + 1 / 2𝑥 + 1 ?
The oblique asymptote of a rational function will exist if the degree of the denominator
is one less than the degree of the numerator.
To find it out, and if the degree of the denominator is equal to 1, you need to divide the
numerator by the denominator using long division, synthetic division, or by factoring if
possible.
Choice B is correct – Applying long
division in our case:
(2𝑥 + 1)
3
/
2
𝑥 -
11
/
4
/
3𝑥2 - 4𝑥 +
1
-
3𝑥2 -
3
/
2
𝑥
-
-
11
/
2
𝑥 + 1
-
11
/
2
𝑥 -
11
/
4
15
/
4
The result of the division will be the equation of the oblique asymptote (without
taking into consideration the remainder).
Therefore: 𝑦=
3
/
2
𝑥 -
11
/
4
equivalent to 𝑦 = 1.5𝑥 - 2.75 in decimal form.
14. 𝑥2 - 6𝑥 + 𝑦2 - 4𝑦 + 2 = 0 represents the equation of a circle (𝐶). What is the radius of this circle?
Separate the equation into expressions in which the first contains the variable 𝑥 and the
second contains the variable 𝑦, then complete the square in each.
Remember that the equation of a circle is: (𝑥 - ℎ)2 + (𝑦 - 𝑘)2 =
𝑟2
with (ℎ, 𝑘) the coordinates of the center of the circle, and 𝑟 its
radius.
Choice C is correct –
Separate/Group the common variables together:
(𝑥2 - 6x) + (𝑦2 - 4𝑦) = -2
To complete the square in 𝑥2 - 6𝑥, we need to add 9. However, the second side
of the equation will have this addition as well.
To complete the square of 𝑦2 - 4𝑦, we need to add 4. Add it as well to the
second side of the equation.
This will result:
(𝑥2 - 6𝑥 + 9) +
(𝑦2 - 4𝑦 + 4) = -2 + 9 + 4
Using perfect squares:
(𝑥 - 3)2 + (𝑦 - 2)2 = 11
Hence, 𝑟2 = 11 so 𝑟 = √11.
15. 𝐴(-5.84, 2.27, 0) and 𝐺(-3, 2, 0) are two vertices of a cube 𝐴𝐺𝐶𝐹𝐸𝐷𝐵𝐻. What is the surface area of this cube?
The area of a cube is 6𝑎2, while the distance between two points in a
3D-coordinate plane is
√(𝑥2 -
𝑥1)2 + (𝑦2- 𝑦1)2 +
(𝑧2 - 𝑧1)2
.
Choice C is correct – The distance
between 𝐴 and 𝐺 is:
√(-3 + 5.84)2 + (2 -
2.27)2 + (0 - 0)2 = 2.8528
Hence: 𝐴 = 6𝑎2 = 6(2.8528)2 = 48.83 square units.
16. Using the diagram below, what is the measure of ∠𝐵𝐷𝐶?
To solve this question, you need to think of the basic relations between angles.
Choice E is correct - ∠𝐸𝐷𝐴 and
∠𝐹𝐷𝐵 are vertically opposite angles, which means 𝑚∠𝐸𝐷𝐴 = 𝑚∠𝐹𝐷𝐵
= 2𝑥 + 15.
∠𝐹𝐷𝐵 and ∠𝐵𝐷𝐶 are complementary angles as the figure shows.
Then:
𝑚∠𝐹𝐷𝐵 + 𝑚∠𝐵𝐷𝐶 = 90°
2𝑥 + 15 +𝑚∠𝐵𝐷𝐶 = 90
𝑚∠𝐵𝐷𝐶 = 90 - 2𝑥 -15
𝑚∠𝐵𝐷𝐶 = 75 - 2𝑥
17. Which of the following is equivalent to the expression: 2𝑎2 - 3𝑎 + 4𝑏𝑎 - 6𝑏?
If you have four terms with no 𝐺𝐶𝐹, then try factoring by grouping.
Choice D is correct – Grouping the
expression:
(2𝑎2 - 3𝑎) + (4𝑏𝑎 - 6𝑏)
Find the greatest common factor 𝐺𝐶𝐹 of each group of terms:
𝑎(2𝑎 - 3) + 2𝑏(2𝑎 - 3)
Then: (2𝑎 - 3)(𝑎 + 2𝑏)
18. Jimmy decided to spend an average of $40 a week on buying clothes. He spent $25 the first week, and $66 the second week. How much can he equally spend the third and the fourth week without surpassing his budget?
To find the average of a set of numbers, add all numbers and divide the answer by how many
numbers there are.
Choice C is correct – First,
consider yourself finding the average.
However, since Jimmy will equally spend the third and the fourth week on buying clothes,
then variable 𝑥 represents the amount spent by Jimmy during each week.
25 + 66 + 𝑥 + 𝑥
/
4
= 40 (Remember that they gave
you the average which is equivalent to 40)
Solving for 𝑥:
91 + 2𝑥 = 160
2𝑥 = 69
𝑥 = 34.5
19. The height of a trapezoid is equal to 2𝑥 + 1. Its small base is half the height, and the large base is triple the small one. What is the expression that represents the area of this trapezoid?
Relate the small base of the trapezoid to its height and its given expression.
Do the same thing again for the large base! Remember that the area of a trapezoid is
represented
by: 𝐴 =
1
/
2
ℎ(𝑏1 + 𝑏2), with ℎ the height of the trapezoid,
𝑏1 its small base, and 𝑏2 its large base.
Choice B is correct – The height is
already given by ℎ = 2𝑥 + 1. Since the small base is half the height,
then 𝑏1 =
ℎ
/
2
=
2𝑥 + 1
/
2
= 𝑥 +
1
/
2
.
The large base is triple the small one. Hence: 𝑏2 = 3𝑏1 = 3(𝑥 +
1
/
2
) = 3𝑥 +
3
/
2
.
Substituting ℎ, 𝑏1, and 𝑏2 by the expressions found:
𝐴 =
1
/
2
(2𝑥 + 1)(𝑥 +
1
/
2
+ 3𝑥 +
3
/
2
) =
1
/
2
(2𝑥 + 1)(4𝑥 + 2)
=
1
/
2
(2)(2𝑥 + 1)(2𝑥 + 1) =(2𝑥 + 1)2
20. What is the product of the solutions of 𝑥4 - 3𝑥2 = -2 ?
Choice D is correct – In this
question, consider another variable 𝑢 such that 𝑢 = 𝑥2. We will have
𝑢2 = 𝑥4.
Substituting 𝑥2 by 𝑢 and 𝑥4 by 𝑢2 in the given
equation:
𝑢2 - 3𝑢 = -2
𝑢2 - 3𝑢 + 2 = 0
The two solutions for 𝑢 are:
𝑢 = 2 or 𝑢 = 1
Therefore:
𝑥2 = 2 or 𝑥2 = 1
𝑥 = ±√2 or 𝑥 = ±1
The product of all the solutions: √2 ∙ (-√2) ∙ 1 ∙ (-1) = 2
21. What are the transformations of 𝑓(𝑥) = 𝑥2 when the graph of 𝑔(𝑥) = 2𝑥2 - 2 is sketched?
To solve this question, you need to remind yourself of the following:
- A function 𝑓(𝑥) is horizontally shifted if
𝑔(𝑥) = 𝑓(𝑥 ± ℎ).
If ℎ > 0, then shifted ℎ units to the left.
If ℎ < 0, then shifted ℎ units to the right.
- A function 𝑓(𝑥) is vertically shifted if 𝑔(𝑥) = 𝑓(𝑥) ± 𝑘.
If 𝑘 > 0, then shifted 𝑘 units up.
If 𝑘 < 0, then shifted 𝑘 units down.
- If 𝑔(𝑥) = -𝑓(𝑥), then it is reflected about the 𝑥-axis.
- If 𝑔(𝑥) = f(-𝑥), then it is reflected about the y-axis.
- If 𝑔(𝑥) = 𝑐 𝑓(𝑥) with 𝑐 > 1, then it is vertically stretched by a factor
of 𝑐.
- If 𝑔(𝑥)) = 𝑐 𝑓(𝑥) with 0 < c < 1, then there is a vertical shrink by a factor
of
1
/
𝑐
.
Choice A is correct – The
subtraction of 2 means
that we have a vertical shift, and since -2 < 0, then the function is
vertically shifted 2 units down.
Multiplying 𝑥2 by 2 and since 2 > 1, then the function is vertically
stretched by a factor of 2.
22. Lora went to the mall and purchased the items that are shown in the adjacent table. What is the sum of the mean and the median of the list shown?
Items | Price |
Jeans | $44.77 |
T-shirt | $25.67 |
Sweatshirt | $20.67 |
Backpack | $24.67 |
Jacket | $67.77 |
Hat | $20.17 |
The mean of a set of numbers is the average of the numbers. The median is the number in
the middle of the set.
Choice D is correct – To find the
mean of the set of numbers, add them
and divide the answer by how many numbers there are:
44.77 + 25.67 + 20.67 + 24.67 + 67.77 + 20.17
/
6
= 33.95
To find the median of the set, arrange all the numbers first from smallest to largest:
20.17; 20.67; 24.67; 25.67; 44.77; 67.77
Then, since we have an even number of numbers (6), then the median will be between 24.67
and 25.67. Consequently,
24.67 + 25.67
/
2
= 25.17
Now adding the mean and the median:
33.95 + 25.17 = 59.12
23. Which constant should be added to 3𝑥2 - 8𝑥 in order to be made into a perfect square?
Choice B is correct – First step is
to divide each term in the expression by the value of 𝑎.
3𝑥2 / 3 - 8𝑥 / 3 = 𝑥2 - 8 / 3 𝑥
To complete the square of this expression, find the square of half of 𝑏:
(
8
/
3
÷ 2)2 =
16
/
9
24. The area of a parallelogram is 16 𝑚2. The ratio of its height to base is 1:4. What is the dimension of its height?
The area of a parallelogram is 𝐴 = 𝑏ℎ.
Choice A is correct – The question
stated that “the ratio of its height
to base is 1:4”, then
ℎ
/
𝑏
=
1
/
4
, equivalent to 4ℎ = 𝑏
As well, the area of the parallelogram is 16 𝑚2. Hence,
𝑏ℎ = 16.
Substituting 𝑏 by 4ℎ:
4ℎ(ℎ) = 16
4ℎ2 = 16
ℎ2 = 4
ℎ = 2
25. Which value for the dimension of segment 𝐴𝐵 could be true so that 𝐴𝐵𝐶 can be a triangle?
Use the inequalities in one triangle to solve this question.
Choice E is correct – Consider the
dimension of segment 𝐴𝐵 is 𝑥. We will have:
𝑥 + 7 > 11 so 𝑥 > 4
and 𝑥 + 11 > 7 so 𝑥 > -4
and 11 + 7 > 𝑥 so 18 > 𝑥 or 𝑥 < 18
Therefore, 𝑥 is any value between 4 and 18.
All values are rejected except for 4.5.
26. Using the adjacent diagram, if lines 𝑚 and 𝑛 are parallel, what is the value of 𝑦?
Use the alternate exterior angles theorem to solve this question.
Choice E is correct – Using
alternate exterior angles theorem, we have:
2𝑥 + 5 = 3𝑥 - 15
Solving for 𝑥:
2𝑥 - 3𝑥 = -15 - 5
-𝑥 = -20
𝑥 = 20
The angles with values 2𝑥 + 5 and 5𝑦 + 35 are supplementary angles.
Thus: 2𝑥 + 5 + 5𝑦 + 35 = 180
2(20) + 5 + 5𝑦 + 35 = 180
5𝑦 + 80 = 180
5𝑦 = 100
𝑦 = 20
27. Which of the following is the inverse function of 𝑓(𝑥) = 𝑥2 - 4𝑥 + 4 ?
The inverse function in Mathematics is a function that reverses another one.
Choice D is correct - 𝑓(𝑥) =
𝑥2 - 4𝑥 + 4 can be written as:
𝑓(𝑥) = (𝑥 - 2)2
Then 𝑦 = (𝑥 - 2)2
𝑥 = (𝑦 - 2)2
Solving for 𝑦:
±√𝑥 = 𝑦 - 2
𝑦 = 2 ± √𝑥
Thus, 𝑓-1(𝑥) = 2 ± √𝑥
28. Which of the following is equivalent to 𝑓(𝑥) = 343(7-2𝑥) ?
Think of a way to simplify this expression using laws of exponents.
Choice B is correct - If 𝑓(𝑥) =
343(7-2𝑥) and 73 = 343, then:
𝑓(𝑥) = 73(7-2𝑥)
Using laws of exponents:
𝑓(𝑥) = 73-2𝑥
29. The perimeter of an equilateral triangle is equal to 3√7- 6. What is the dimension of the height of the triangle?
In an equilateral triangle, all sides are congruent. For that reason, the perimeter is
triple one of the sides: 𝑃 = 3𝑠.
Choice C is correct – The perimeter
of this equilateral triangle is
3√7 - 6. It means that
each side has a dimension equal to
3√7
/
3
-
6
/
3
= √7 - 2
Since in an equilateral triangle, each angle is equal to 60°, then drawing the height of
this triangle will divide it into two 30° -60° -90° triangles.
Working on one of the triangles, the height is ℎ and is considered as the large side of
this new triangle.
The small side (𝑠) of this triangle is equal to the side of the equilateral triangle
divided by 2 (The height in an equilateral
triangle is at the same time the median of this triangle). It is equivalent to
√7
/
2
- 1. And the hypotenuse of this special right triangle is equal to the
side of the equilateral triangle.
Hence, in a 30° -60° -90°, the large side is equal to the small side multiplied
by √3,
so: ℎ = 𝑠√3 in our
case, which leads us to:
ℎ = ( √7 / 2 - 1)(√3) = √21 / 2 - √3 = 0.56
30. Which of the following equations has roots equal to 2 √2 and - 7 / 2 ?
The best way to solve this question is by substituting 𝑥 in each equation by the values
given in order to check whether they both could be roots of the equation or not.
Checking option A:
if 𝑥 = 2√2, then 0 = (2√2)2 + (2√2)(
-7 + 4√2
/
2
) - 7√2
We will have: 0 = 8 + 8 - 7√2 -
7√2
0 = 16 - 14√2 which is
incorrect.
Since 2√2 is not a root for option
A, then it is useless to check 𝑥 = -
7
/
2
.
Checking option B:
if 𝑥 = 2√2, then 0 = (2√2)2 + (2√2)(
7 - 4√2
/
2
) - 7√2.
We will have: 0 = 8 - 8 + 7√2 -
7√2
0 = 0, then 2√2 is a root for the
equation.
if 𝑥 = -
7
/
2
, then 0 = (-
7
/
2
)2 + (-
7
/
2
)(
7 - 4√2
/
2
) - 7√2
We will have: 0 =
49
/
4
+
-49 + 28√2
/
4
- 7√2.
0 =
49
/
4
-
49
/
4
+ 7√2 -7√2
0 = 0, then -
7
/
2
is a root for the equation.
Choice B is correct.
31. Jack bought a bag of 30-pieces of chocolates in which he found three different types of chocolate bars. If there are 11 bars of type A, 13 bars of type B, and the remaining are bars of type C, what is the probability that the first bar of chocolate that Jack will choose will be of type C?
This is a probability question which is direct to the point, but only after finding how
many chocolate bars of type C there are already in the bag.
Choice D is correct – To find the
number of chocolate bars of type C in the bag, subtract the
number of bars of type A, and the number of bars of type B, from the total number of bars
in the bag:
30 - 11 - 13 = 6, then there are 6 chocolate bars of type C in the bag.
The probability of choosing the first bar of chocolate from the bars of type C is 𝑃(𝐶) =
number of bars of type 𝐶
/
total number of bars
=
6
/
30
=
1
/
5
32. Using the adjacent figure, the length of the larger rectangle is 8𝑥 + 1 while the width is equal to 4𝑥 + 3. If the area of the shaded region is equal to 204 square units, what is the value of 𝑥?
To find the area of the shaded region (grey part), subtract the area of the unshaded
region (small white rectangle) from the total area of the whole rectangle.
Choice C is correct – To find the
total area of the rectangle, multiply its length by its width:
𝐴 = 𝐿 ∙ 𝑤 = (8𝑥 + 1)(4𝑥 + 3)
Expanding it will result: 𝐴=32𝑥2 + 28𝑥 + 3
To find the area of the small white rectangle, we need its length and its width.
To find its width, we need to subtract (𝑥 + 𝑥) = 2𝑥 from the width of the larger
rectangle:
(4𝑥 + 3) - 2𝑥 = 2𝑥 + 3.
While 2𝑥 should be subtracted from the length of the larger rectangle in order to find
the length of the small white rectangle:
(8𝑥 + 1) - 2𝑥 = 6𝑥 + 1
Now its area is:
𝐴𝑢𝑛𝑠 = (6𝑥 + 1)(2𝑥 + 3) =12𝑥2 + 20𝑥 + 3
Subtracting both areas as mentioned before to find the area of the shaded region:
𝐴𝑠 = 𝐴 - 𝐴𝑢𝑛𝑠 = (32𝑥2 + 28𝑥 + 3) -
(12𝑥2 + 20𝑥 + 3)
=32𝑥2 + 28𝑥 + 3 - 12𝑥2 - 20𝑥 - 3
=20𝑥2 + 8𝑥
However, since the area of the shaded region is equal to 204 square units, then: 20𝑥2 + 8𝑥 = 204
20𝑥2 + 8𝑥 - 204 = 0
As this is a quadratic equation, the two solutions are:
𝑥 = -3.4 which is rejected, or 𝑥 = 3 which is accepted.
33. The adjacent table shows the heights of 10 randomly chosen buildings in Egypt. What is the sum of the interquartile range and the median of the data shown?
Building | Height (m) |
Cairo Tower | 187 |
Ministry of Foreign Affairs Building, Cairo | 143 |
Nile City South Tower | 142 |
El Maadi Residential Tower 16 | 140 |
Great Pyramid of Giza | 138.8 |
National Bank of Egypt Tower 1 | 135 |
Residences Roda Island | 118 |
Ramses Hilton & World Trade Center | 110 |
Hilton World Trade Center Residences | 110 |
Four Seasons Cairo at First Residence | 103 |
Interquartile range and median are parts of statistics. It is important to know that you
need to arrange your data from smallest to greatest.
Choice E is correct – The range
from smallest to greatest is:
103, 110, 110, 118, 135, 138.8, 140, 142, 143, 187
There are 10 data in this set. To find its median, find the average of the 5th and 6th numbers:
135 + 138.8 / 2 = 136.9
The interquartile range is a measure of statistical dispersion.
It is equivalent to the difference between the upper quartile (75th
percentile) and the lower quartile (25th percentile).
This data is to be divided into two as each 5 numbers will be together in a
group:
1st group: 103, 110, 110, 118, 135 – The middle number is 110,
which is considered as the lower quartile.
2nd group: 138.8, 140, 142, 143, 187 – The middle number is 142,
which is considered as the upper quartile.
Therefore, the interquartile range is 𝑈𝑄 - 𝐿𝑄 = 142 - 110 = 32.
The sum of the two values found: 136.9 + 32 = 168.9
34. The adjacent figure shows two similar triangles. What is the area of the larger triangle?
Use Thales’ property and Pythagorean theorem to find the missing lengths in each triangle
in order to find the area of the larger triangle.
Choice C is correct – First, let us
find the missing length (base) of the small right triangle,
using Pythagorean theorem (𝑐2 = 𝑎2 + 𝑏2). The
hypotenuse is equal to 18, and the small leg is 10.
Therefore, the base 𝑥 is: 182 = 102 + 𝑥2
𝑥2 = 224
𝑥 = 4√14
Applying Thales’ property, and considering 𝑦 as the height of the larger right triangle:
𝑦
/
10
=
20
/
4√14
𝑦 = 13.363
The area of the triangle is: 𝐴 = 1 / 2 𝑏ℎ = 1 / 2 (20)(13.363) = 133.63 square units.
35. Which of the following is not a solution of |-8 + 3𝑥| - 2 < 3 ?
Solve the inequality involving absolute value, then compare the values given.
Choice E is correct – The
inequality |-8 + 3𝑥| - 2 < 3 will result two inequalities not involving
absolute value:
-8 + 3𝑥 - 2 < 3 and -(-8 + 3𝑥) - 2 < 3
3𝑥 < 13 and -3𝑥 < -3
𝑥 <
13
/
3
and 𝑥 > 1
Consequently, any value between 1 and
13
/
3
= 4.33 is correct. Since
19
/
20
= 0.95 < 1 and not included in the range of values that are
correct, then 0.95 cannot be a solution.
36. In a triangle 𝑇𝑅𝐷, 𝑚∠𝑇 = 66° while sec𝑅 = 1.887. What is the measure of angle 𝐷?
Remember that secα =
1
/
cosα
, then cosα =
1
/
secα
.
Choice A is correct – Since sec𝑅
= 1.887, then cos𝑅 =
1
/
1.887
= 0.5299.
To find 𝑚∠𝑅:
𝑚∠𝑅 =cos-10.5299 = 57.99 ≅ 58°.
In a triangle, the sum of the measures of the interior angles is 180°:
37. The polynomial 2𝑥3 - 𝑎𝑥2- 7𝑥 + 6 has no remainder when it is divided by 𝑥 - 1. What is the value of 𝑎?
You can use synthetic division to find the remainder of the division of the polynomial by
𝑥 - 1 when a exists.
Choice D is correct – The division
of the polynomial by 𝑥 - 1 using
synthetic division is:
38. The area of the shaded region in the adjacent circle is equal to 42.75π square units. The circumference of the smaller circle is equal to 5π units. What is the radius of the larger circle?
Remember that the circumference of a circle is equal to 2π𝑅 with 𝑅 being the radius of
the circle. Its area is equal to π𝑅2.
Choice B – First, using the
circumference formula, find the radius R of the small circle:
2π𝑅 = 5π
Then: 𝑅 =
5
/
2
.
The area of this small circle will be: 𝐴 = π𝑅2= π(
5
/
2
)2 =
25π
/
4
.
Adding the area of the small circle to the area of the shaded region will result the
area 𝐴' of the larger circle:
𝐴' = 42.75π + 6.25π = 49π.
Hence: 49π = π𝑟2
𝑟2 = 49
𝑟 = 7 units
39. What is the equation of the line parallel to the line with equation √2𝑥 - 3𝑦 = 1 and passing through the center of the circle with equation (𝑥 - 3√2)2 + (𝑦2 - 8𝑦 + 16) = 25?
Find the center of the circle using the equation of the circle, and remember that two
lines are parallel if their slopes are equal.
Choice A is correct – The equation
(𝑥 - 3√2)2 +
(𝑦2 - 8𝑦 + 16) = 25
shows that the abscissa of the center of the circle is 3√2. Factoring
𝑦2 - 8𝑦 +16 will result: (𝑦 - 4)2, and then the
ordinate of the center of the circle is 4.
Line √2𝑥 - 3𝑦 = 1 can be written
as: 3𝑦
= √2𝑥 - 1
𝑦 = √2 / 3 𝑥 - 1 / 3
The line parallel to it will have the same slope =
√2
/
3
.
Hence: 𝑦 =
√2
/
3
𝑥 + 𝑏
It is passing through point (3√2; 4), then:
4 = √2 / 3 (3√2) + 𝑏
Solving for 𝑏:
𝑏 = 2
The equation of the line is: 𝑦 = √2 / 3 𝑥 + 2
40. In the adjacent figure, 𝑚∠𝐴𝐵𝐷 = 2 / 3 𝑚∠𝐶𝐵𝐸. What is the value of 𝑥 ?
Choice B is correct – Consider 𝑚∠𝐴𝐵𝐶 = 𝑦. The sum of the measures of the interior angles in a triangle is 180°. Then:
𝑥 + 50 + 3𝑥 - 5 + 𝑦 = 180
4𝑥 + 𝑦 = 135
𝑦 = -4𝑥 + 135
Given that 𝑚∠𝐴𝐵𝐷 = 2 / 3 𝑚∠𝐶𝐵𝐸, then: 2𝑥 + 15 = 2 / 3 𝑚∠𝐶𝐵𝐸
𝑚∠𝐶𝐵𝐸 = 3𝑥 + 22.5
From the figure, we have ∠𝐴𝐵𝐷, ∠𝐴𝐵𝐶 and ∠𝐶𝐵𝐸 are supplementary angles.
Hence:
2𝑥 + 15 + (-4𝑥 + 135) + 3𝑥 + 22.5 = 180
𝑥 + 172.5 = 180
𝑥 = 7.5
41. Which of the following expressions is equivalent to 3√135𝑥5𝑦7 . √180𝑥3𝑦 ?
Choice E is correct – The
expression
3√135𝑥5𝑦7
. √180𝑥3𝑦
can be simplified as:
3𝑥𝑦23√5𝑥2𝑦 . 6𝑥√5𝑥𝑦
= 18𝑥2𝑦2 (5 1 / 3 𝑥 2 / 3 𝑦 1 / 3 ) . (5 1 / 2 𝑥 1 / 2 𝑦 1 / 2 )
= 18𝑥2𝑦2
(5
5
/
6
𝑥
7
/
6
𝑦
5
/
6
)
= 18𝑥2𝑦2 6√55𝑥7𝑦5
= 18𝑥2𝑦2 . 𝑥 6√55𝑥𝑦5
= 18𝑥3𝑦2 . 6√55𝑦5𝑥
3 | 1 |
0 | 5 |
2 | 4 |
3 | 4 |
-2 | 4 |
5 | 3 |
9 | 6 |
3 | -2 |
-1 | 9 |
10 | 11 |
20 | 16 |
9 | 0 |
1 | -3 |
5 | 8 |
11 | 10 |
6 | 2 |
7 | -1 |
11 | 10 |
16 | 20 |
0 | 9 |
7 | -7 |
-10 | -1 |
-16 | -8 |
-3 | 8 |
9 | 0 |
20 | 16 |
10 | 11 |
-1 | 7 |
-2 | 4 |
5 | 3 |
9 | 6 |
3 | -2 |
-4 | 8 |
10 | 6 |
18 | 12 |
6 | -4 |
3 | 1 |
0 | 5 |
2 | 4 |
3 | 4 |
-4 | 8 |
10 | 6 |
18 | 12 |
6 | -4 |
-1 | 9 |
10 | 11 |
20 | 16 |
9 | 0 |
43. Given 𝐴(2, 3, -7) and 𝐵(3𝑚, -2𝑚 + 1, 6). What is the value of 𝑚 if 𝐴𝐵2 = 221 ?
In a 3D-coordinate system, the distance between two points is:
√ (𝑥2 - 𝑥1)2 +(𝑦2 - 𝑦1)2+(𝑧2 - 𝑧1)2
Choice D is correct – The distance
between 𝐴 and 𝐵 is
𝐴𝐵 = √
(2 - 3𝑚)2 + (3 + 2𝑚 - 1)2 + (-7 - 6)2
𝐴𝐵 = √
(2 - 3𝑚)2 + (2 + 2𝑚)2 + 169
𝐴𝐵 = √
4 - 12𝑚 + 9𝑚2 + 4 + 8𝑚 + 4𝑚2 + 169
𝐴𝐵 = √
13𝑚2 - 4𝑚 + 177
Since 𝐴𝐵2 = 221, then 221 = 13𝑚2 - 4𝑚 + 177
13𝑚2 - 4𝑚 - 44 = 0
The solutions of this quadratic equation are: 2 or -1.69 ≅ -1.7
Then choice D is to be chosen.
44. If 𝑓(𝑥) = 2 ∙ 3𝑥 + 2, which of the following statements is correct?
𝑓(𝑥) is an exponential function such that its general form is
𝑦 = 𝑎 × 𝑏𝑥 - 𝑐 + 𝑑.
Choice B is correct – In this
function 𝑓(𝑥) = 2 ∙ 3𝑥 + 2, we have:
𝑎 = 2
𝑏 = 3
𝑐 = 0
𝑑 = 2
Since 𝑎 = 2 > 0 and 𝑏 = 3 > 1, then the graph of this function is increasing.
Since 𝑑 = 2 then 𝑦 = 2 is the equation of the horizontal asymptote of this function.
45. Given 𝑓(𝑥) = 3𝑥2 - 6𝑥 + 1. What is the product of the coordinates of the vertex of this function?
To find the coordinates of the vertex of the graph of a quadratic function, find
the equation of the axis of symmetry (it will represent the abscissa of the vertex), then
replace 𝑥 by its value in the equation to find the ordinate of the vertex.
Choice C is correct – The equation
of
the axis of symmetry of 𝑓, is:
𝑥 = - 𝑏 / 2𝑎 = -(-6) / 2(3) = 1
Then: 𝑦 = 3(1)2 - 6(1) + 1 = -2.
The vertex has the coordinates (1,-2). The product of the abscissa and the ordinate is:
1 × -2 = -2
46. Using the adjacent diagram, what is the value of 2𝑥 / 𝑦 ?
Choice E is correct – Using alternate exterior angles theorem:
3𝑥 - 5 = 4𝑦 + 14
The angle with measure (4𝑦 + 14) is vertically opposite angle with the angle that is considered with the angle of measure 92.1° as interior angles on the same side of the transversal (these two angles are supplementary).
Then 4𝑦 + 14 = 180 - 92.1
4𝑦 = 73.9
𝑦 = 18.475
Therefore: 3𝑥 - 5 = 4(18.475) + 14
3𝑥 - 5 = 87.9
3𝑥 = 92.9
𝑥 = 30.96
We will have: 2𝑥 / 𝑦 = 2(30.96) / 18.475 = 3.35
47. If 21𝑥 - 𝑖 + 8𝑦 = 7𝑥𝑖 + 2𝑦 - 1 , what real values of 𝑥 and 𝑦 satisfy the equation?
Choice A is correct – Compare the
real parts alone, then the imaginary parts.
We will have for the real parts: 21𝑥 + 8𝑦 = 2𝑦 - 1
21𝑥 + 6𝑦 = -1
For the imaginary parts: -1 = 7𝑥
𝑥 = - 1 / 7
Substituting 𝑥 by - 1 / 7 in 21𝑥 + 6𝑦 = -1:
21(-
1
/
7
) + 6𝑦 = -1
-3 + 6𝑦 = -1
𝑦 =
1
/
3
48. Which of the following expressions can never have a negative answer for any 𝑥?
Analyze each expression alone.
Choice A is: |2𝑥 - 3(𝑥 - 5)| - 1.
The absolute value is always positive, then |2𝑥 - 3(𝑥 - 5)|
is positive. However, it can be between 0 and 1, and then we will have in
that case, after subtracting 1, a negative value. Choice A is incorrect.
Choice B is:
𝑥2 - 𝑥 - 6
/
𝑥4
. The denominator has an even power, and then it will be always positive.
However, the quadratic expression in the numerator might be positive or
negative (take 𝑥 = -1 as an example), and then the expression
can be positive or negative as well. Choice B is incorrect.
Choice C is: (-2|𝑥 - 3|)2 - 3. The parenthesis (-2|𝑥 - 3|)2 is
always positive
as it is to the power of an even number. However, subtracting the answer
by 3 might result a negative answer. Choice C is incorrect.
Choice D is:
𝑥2 + 3
/
(𝑥 - 7)2
. The denominator is to the power of an even number
so it is always positive. The numerator has the expression 𝑥2 + 3.
Nonetheless, 𝑥2 is always positive, and adding 3 will make the answer to
remain positive.
Therefore, the answer of this expression is always positive and never negative.
Choice D is correct.
It is useless to check choice E, but to explain it: (𝑥 - 1)3 is to the power
of an odd number, and then it could be positive or negative according to the value you
will have inside the parenthesis.
49. Ahmad bought 7 pencils and 11 pens from a shop for $11.2. The price of 5 pens is equal to the price of 7 pencils. What is the price of 3 pens?
This question is to be solved using a system of equations.
Choice D is correct – Define two
variables:
Let 𝑥 be the price of one pencil, and 𝑦 the price of one pen.
We will have: 7𝑥 + 11𝑦 = 11.2 and 5𝑦 = 7𝑥.
Solving for 𝑥 in the second equation:
𝑥 =
5
/
7
𝑦.
Substituting 𝑥 by
5
/
7
𝑦 in the first equation:
7(
5
/
7
𝑦 )+ 11𝑦 = 11.2
5𝑦 + 11𝑦 = 11.2
16𝑦 = 11.2
𝑦 = 0.7
The price of a pen is $0.7.
Hence, the price of 3 pens is: 3(0.7) = $2.1
50. A group of 7 persons is to be chosen from 5 men and 4 women. If at least 3 women should be included, in how many ways can this be done?
Tackle this question by understanding first its main concept; having at
least 3 women in the chosen group means we could have the following possibilities:
The group might have 3 women and 4 men, or 4 women and 3 men. It cannot have 5 women since
the maximum number of women to choose from is 4.
Choice B is correct – In this
question, we need to apply the concept of combinations which determines the number of
possible arrangements taking into consideration that the order of the selection does not
matter.
Therefore, for the first group (3 women chosen from 4, and 4 men chosen from 5), we have:
𝐶34 . 𝐶45 = 4 × 5 = 20.
For the second group (4 women chosen from 4, and 3 men chosen from 5), we have:
𝐶44 . 𝐶35 = 1 × 10 = 10
Adding both answers will result: 20 + 10 = 30 ways.
THE FORMULAS BELOW MAY BE USEFUL IN ANSWERING QUESTIONS ON THIS
TEST.
𝑠 = 4π𝑟2 is the formula for the surface area of a sphere with a radius
of 𝑟.
𝑉 =
1
/
3
π𝑟2ℎ is the formula for a right circular cone with a radius of 𝑟
and a height of ℎ.
𝑉 =
4
/
3
π𝑟3 is the formula for a sphere with a radius of 𝑟.
𝑉 =
1
/
3
𝐵ℎ is the formula for a pyramid with a base area of 𝐵 and a height of ℎ.