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Probability
1. Marty has a jumble of socks in his drawer. If he picks a pair of socks randomly
from his drawer, what is the probability Marty will pick a gray pair of socks?
A.
B.
C.
D.
Each set of two socks is a pair.
b = blue, r = red, g = gray
2. Tyrone randomly drew pieces of paper numbered 10 through 50 out of a bowl.
After he drew each piece of paper, he recorded the number, returned the piece
of paper to the bowl, and then drew the next piece of paper. His results are
recorded in the stem-and-leaf plot below.
1
2
3
4
1
0
0
3
1
1
0
4
2
2
1
4
3
2
2
5
4
2
3
6
4
3
4
7
5
4
5
8
7
6
5
8
8
8
6
9
9
7
A.
B.
9
9
Key: 1 6 represents 16
Based on the information in the stem-and-leaf plot, what is the experimental
probability that a piece of paper randomly drawn from the bowl will have the
number 35 written on it?
C.
D.
3. The possible outcomes for rolling a pair of fair dice are shown below.
A.
B.
C.
D.
What is the probability of rolling a composite number?
A.
4. Charisma is getting a gumball out of the gumball
machine. There are 21 red gumballs, 19 blue gumballs,
11 yellow gumballs, 19 purple gumballs, and 15 white
gumballs in the machine. What is the probability that
Charisma gets a gumball that is not yellow?
B.
C.
D.
5.
Prudence has 16 pairs of gold earrings and 8 pairs
of silver earrings in a drawer in her jewelry box. If
she randomly pulls six pairs of earrings out of the
drawer to take with her on a trip, which of the
following is the best prediction of the number of
earrings that will be gold?
A. 5
B. 4
C. 8
D. 2
A.
6.
A class has 26 students. Each student has to present a project to the
class. To decide the order, the teacher writes every letter in the
alphabet on pieces of paper and puts it in a hat. What is the probability
that the first letter drawn is not a vowel?
B.
C.
D.
A. 12
7. A ticket brokering company is randomly distributing tickets to customers who
pre-ordered tickets for an upcoming concert. Out of the first batch of tickets sent
to pre-order customers, 20 are in row 7, 21 are in row 8, and 14 are in row 9.
Which of the following is the best prediction of the number of tickets in row 7 in
the next 33 tickets sent out?
B. 10
C. 13
D. 4
8. Becky has a cup of pens, pencils, and stick erasers on her desk.
A.
B.
C.
If Becky picks one of these objects randomly from the cup, what is the
probability she will pick a pencil?
D.
9. Tameka bought three dozen donuts to take into work. There are 15 cake donuts,
7 glazed donuts, 8 chocolate donuts, and 6 blueberry donuts. If she randomly
gives donuts to 12 of her coworkers, which of the following is the best prediction
of the number of coworkers that will receive a cake donut?
A. 3
B. 5
C. 2
D. 4
10.
A.
Dylan is playing pool with his friend. On the table,
there are 7 solids, 7 stripes, and the eight-ball which
counts as neither a solid nor a stripe. On the first
shot, one of the balls goes into a pocket. What is the
probability that the ball is not a solid? (Assume each
ball is equally likely to go into the pocket.)
B.
C.
D.
11. Belle is playing a game where the probability of drawing a card with a value
greater than 12 is
. If she draws 80 cards throughout the game, which of the
following is the best prediction of the number of cards she will draw with a value
greater than 12?
A. 5
B. 11
C. 4
D. 7
12. The possible outcomes for tossing a coin four times are
shown below.
1. T-TT-T
5. T-HT-T
H-TT-T
13. H-HT-T
2. T-TT-H
6. T-HT-H
H-T10.
T-H
14. H-HT-H
3. T-TH-T
7. T-HH-T
11.
H-TH-T
15. H-HH-T
4. T-TH-H
8. T-HH-H
12.
H-TH-H
16. H-HH-H
Tails = T
9.
A.
B.
C.
D.
Heads = H
If a coin is tossed four times, what is the probability of
getting 1 head?
13. Elliott used a random number generator to perform a probability experiment. The
numbers generated are recorded in the stem-and-leaf plot below.
6
7
8
9
1
0
0
1
2
1
1
2
2
1
2
3
3
2
3
4
4
3
4
5
5
3
4
6
5
3
5
7
6
5
6
7
7
7
9
8
8
8
10 0
0
1
2
3
3
4
5
6
8
9
8
9
Based on the information in the stem-and-leaf plot, what is the experimental
probability that the next number generated will be 73?
A.
B.
C.
D.
14. A furniture store recorded the number of dining table chairs that were sold in the
last week in five different price ranges.
A.
B.
C.
D.
Based on the information in the graph, what is the experimental probability that
the next chair sold will cost from $250 to $299?
15.
Thirty slips of paper, numbered 1 to 5 are placed in a paper bag. One slip of paper
is drawn at random.
What is the probability of drawing an even number?
A.
B.
C.
D.
Post Test - Math
1. Jody Berman paid $45.50 for 7 pounds of shrimp. How much did she pay per
pound?
A. $6.75
B. $5.35
C. $7.50
D. $6.50
2.
16 yards
11 yards
Kim's field is a triangle with a base of 11 yards and a height of 16 yards. What is
the area of Kim's field?
A. 88 square yards
B. 176 square yards
C. 352 square yards
D. 44 square yards
3. Solve the following.
3 × 0.5 = ?
A. 0.15
B. 1.5
C. 150
D. 2
4. An architect drew the blueprint for a new office building. He used a scale in which
1 inch represents 7.5 feet. The floor of an office in the building will have actual
dimensions of 17 feet by 14 feet. What will be the dimensions on the blueprint?
A. 127.5 inches by 105 inches
B. 9.5 inches by 6.5 inches
C. 24.5 inches by 21.5 inches
D. 2.27 inches by 1.87 inches
5. Simplify the following expression:
4 × 32 + 9 ÷ 3 - (5 + 2)
A. 40
B. 36
C. 41
D. 32
6. Cynthia has more than 4 times as many paper clips as Rizwan. Rizwan has 10
paper clips. Which expression shows C, the number of paper clips that Cynthia
has?
A. C > 4 × 10
B. C > 4 + 10
C. C < 4 × 10
D. C < 4 ÷ 10
7. If Quinn tosses a fair coin and then rolls a fair number cube labeled 1 through 6,
what is the probability of tossing heads followed by rolling a number less than 3?
A. 1/3
B. 1/6
C. 6
D. 1/4
8. An ice skating rink charges a special rate on Wednesday nights. The special rate
includes a one-time charge of $3 to rent skates plus $3 per hour to skate. The
function table below shows the relationship between the number of hours a
person skates and the total cost.
Number of
Total Cost
Hours
1
6
3
12
5
18
6
?
What is the total cost, in dollars, to skate for 6 hours?
A. $21
B. $26
C. $19
D. $28
9. Building A weighs 3,016,137 pounds and Building B weighs 8,975,308 pounds.
What is the best estimate for the combined weight of these buildings?
A. 14,000,000 pounds
B. 12,000,000 pounds
C. 11,000,000 pounds
D. 1,200,000 pounds
10. If a = 8 and b = -16, what is the value of the expression below?
5a + b/a + 3a
A. 63
B. 62
C. 60
D. 64
11.
How many total automobile accidents occured in January?
A. 40
B. 60
C. 50
D. 37
12. What number does the red dot best represent on the number line?
0
A. 7/10
B. 4/5
C. 10/8
D. 9/10
13.
Solve for n:
A. n = 42
B. n = 128
C. n = 37
D. n = 16
4
n
=
8
32
1
14. Ashley wanted to buy a new lamp for her apartment. Before doing this, she
decided to do some research on the prices of lamps. She listed the prices of the
different lamps she found in the stem-and-leaf plot below.
Prices of Lamps
4
3357
5
29
6
3668
7
4
8
0288
How many lamps had a price less than $60?
A. 5
B. 6
C. 15
D. 10
15. Find the missing number in the pattern below.
/5
1
A. 1 2/5
B. 1 3/10
C. 1 1/10
D. 1 1/5
/10
7
?
1 7/10
2 1/5
2 7/10
Probability
Answers
1. A
2. C
3. D
4. A
5. B
6. D
7. A
8. A
9. B
10. A
11. A
12. B
13. B
14. D
15. B
Explanations
1.
2. First, find the total number of pieces of paper drawn from the bowl by finding the total number of
entries in the stem-and-leaf plot.
There are 40 numbers recorded in the stem-and-leaf plot, and two of the entries are 35.
So, two out of 40 pieces of paper drawn had the number 35 written on them.
Therefore, the experimental probability that the piece of paper will have 35 on it is
.
3.
4. If P(A) is the probability that an event will occur, then 1 - P(A) is the probability that the event will
not occur.
To find the probability that the gumball is not yellow, first find P(A), the probability that the gumball is
yellow.
Since the chance that the gumball is yellow is 11 out of 85, the following is true.
Then, find 1 - P(A), the probability that the gumball is not yellow.
So, the probability that the gumball is not yellow is
.
5. First, find the probability of Prudence pulling a gold pair of earrings from the drawer.
Sixteen of the 24 pairs of earrings are gold, so the probability of Prudence pulling a gold pair of
earrings is
.
Next, multiply the number of pairs of earrings Prudence is taking on her trip by the probability to
predict the number of pairs of earrings that will be gold.
Therefore, the best prediction of the number of pairs of earrings that will be gold is 4.
6. If P(A) is the probability that an event will occur, then 1 - P(A) is the probability that the event will
not occur.
To find the probability that the letter drawn is not a vowel, first find P(A), the probability that the
letter drawn is a vowel.
Since the chance that the letter drawn is a vowel is 5 out of 26, the following is true.
Then, find 1 - P(A), the probability that the letter drawn is not a vowel.
So, the probability that the letter drawn is not a vowel is
.
7. First, find the probability of a pre-order customer receiving a ticket in row 7.
Twenty of the 55 tickets are in row 7, so the probability of a customer receiving a ticket in row 7 is
.
Next, multiply the number of tickets sent out next by the probability to predict the number of
customers who will receive a ticket in row 7.
Therefore, the best prediction of the number of customers in the next group who will receive a ticket
in row 7 is 12.
8.
9. First, find the probability of a coworker receiving a cake donut.
Fifteen of the 36 donuts are cake donuts, so the probability of a coworker receiving a cake donut is
.
Next, multiply the number of coworkers by the probability to predict the number of coworkers who will
receive a cake donut.
Therefore, the best prediction of the number of Tameka's coworkers who will receive a cake donut is
5.
10. If P(A) is the probability that an event will occur, then 1 - P(A) is the probability that the event will
not occur.
To find the probability that the ball in the pocket is not a solid, first find P(A), the probability that the
ball in the pocket is a solid.
Since the chance that the ball in the pocket is a solid is 7 out of 15, the following is true.
Then, find 1 - P(A), the probability that the ball in the pocket is not a solid.
So, the probability that the ball in the pocket is not a solid is
.
11. Multiply the number of cards Belle drew by the probability to predict the number of cards she will draw
with a value greater than 12.
Therefore, the best prediction of the number of cards Belle will draw with a value greater than 12 is 5.
12.
13. First, find the total number of numbers generated by finding the total number of entries in the stemand-leaf plot.
There are 51 numbers recorded in the stem-and-leaf plot, and three of the entries are 51.
So, three out of 51 numbers generated were 73.
Therefore, the experimental probability that the number generated will be 73 is
.
14. First, find the total number of dining table chairs that were sold in the last week by adding the number
of chairs sold in each price range.
11 + 3 + 5 + 3 + 7 = 29
Three out of the 29 chairs sold were in the $250 to $299 price range.
Therefore, the experimental probability that the next chair sold costs from $250 to $299 is
15.
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Answers
1. D
2. A
3. B
4. D
5. D
6. A
7. B
8. A
9. B
10. B
11. D
12. B
13. D
14. B
15. D
Explanations
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