Probability Practice Quiz

1) There are 6 red, 5 blue, 3 green and 1 yellow marbles in a jar. Jada picks a marble without looking. What is the probability Jada picks a red or yellow marble?

7/15

2/75

7/30

1/35

red + yellow = 6 + 1 = 7 out of 15 6/15 + 1/15 = 7/15

Explanation

red + yellow = 6 + 1 = 7 out of 15 6/15 + 1/15 = 7/15

2) There are 5 basketballs, 4 soccer balls and 6 footballs in a ball bin. If a student chooses a ball at random from the bin, what is the probability the student will pick a football or a basketball?

11/15

3/4

4/9

13/7

The probability of picking a football or a basketball can be calculated by adding the number of footballs and basketballs and dividing it by the total number of balls in the bin. In this case, there are 5 basketballs and 6 footballs, so the total number of footballs and basketballs is 5 + 6 = 11. The total number of balls in the bin is 5 + 4 + 6 = 15. Therefore, the probability is 11/15.

Explanation

The probability of picking a football or a basketball can be calculated by adding the number of footballs and basketballs and dividing it by the total number of balls in the bin. In this case, there are 5 basketballs and 6 footballs, so the total number of footballs and basketballs is 5 + 6 = 11. The total number of balls in the bin is 5 + 4 + 6 = 15. Therefore, the probability is 11/15.

3) A teacher has 9 red crayons, 4 blue crayons, 7 purple crayons, and 5 black crayons in a basket. A student reaches into the basket and randomly selects a crayon. What is the probability that the crayon will be either red or purple?

9/16

16/25

7/25

7/16

red + purple = 9 + 7 = 16 out of 25
9/25 + 7/25 = 16/25

Explanation

red + purple = 9 + 7 = 16 out of 25
9/25 + 7/25 = 16/25

4) A teacher has 9 red crayons, 4 blue crayons, 7 purple crayons, and 5 black crayons in a basket. A student reaches into the basket and randomly selects a crayon. What is the probability that the crayon will be either blue or black?

4/16

13/25

9/25

9/16

blue + black = 9 out of 25
4/25 + 5/25 = 9/25

Explanation

blue + black = 9 out of 25
4/25 + 5/25 = 9/25

5) Scott rolls a six sided number cube (a dice). What is the probability that the number rolled is an even or a 5?

1/2

1/3

2/3

1/12

even (2, 4, 6) plus 5 = 4 possibilities out of 6

3/6 + 1/6 = 4/6 = 2/3 reduced

Explanation

even (2, 4, 6) plus 5 = 4 possibilities out of 6

3/6 + 1/6 = 4/6 = 2/3 reduced

6) There are 10 red, 5 blue, 3 green and 2 yellow marbles in a jar. Mark picks a marble without looking. What is the probability Mark picks a green or yellow marble?

3/10

1/4

3/5

1/3

green marbles + yellow marbles = 5 total marbles = 20 5/20 = 1/4

Explanation

green marbles + yellow marbles = 5 total marbles = 20 5/20 = 1/4

7) Tre has 5 t-shirts, 4 dress shirts and 3 polo shirts in his closet. If he reaches in without looking what is the probability he will pick a t-shirt or a polo shirt?

8/12 , 2/3

4/6, 12/3

7/15, 12/8

4/6, 12/10

There are a total of 5 t-shirts, 4 dress shirts, and 3 polo shirts in Tre's closet. The probability of picking a t-shirt or a polo shirt can be calculated by adding the number of t-shirts and polo shirts and dividing it by the total number of shirts. Therefore, the probability is 8/12, which simplifies to 2/3.

Explanation

There are a total of 5 t-shirts, 4 dress shirts, and 3 polo shirts in Tre's closet. The probability of picking a t-shirt or a polo shirt can be calculated by adding the number of t-shirts and polo shirts and dividing it by the total number of shirts. Therefore, the probability is 8/12, which simplifies to 2/3.

8) Jalen rolls a six sided number cube (a dice). What is the probability that the number rolled is a 2 or a number greater than 3?

2/3

1/2

5/6

1/9

1/6 +3/6= 4/6 = 2/3 reduced
possible outcomes: 2, 4, 5, 6 (that is four)
total outcomes: 1, 2, 3,4 ,5 ,6 (that is six)
possible/total = 4/6 = 2/3

Explanation

1/6 +3/6= 4/6 = 2/3 reduced
possible outcomes: 2, 4, 5, 6 (that is four)
total outcomes: 1, 2, 3,4 ,5 ,6 (that is six)
possible/total = 4/6 = 2/3

9) From a standard deck of cards, find the probability of picking a queen or an even number.

4/13

6/13

6/169

5/13

4/52 + 20/52 = 24/52 which reduces to 6/13
number of queens = 4, number of even (2, 4, 6, 8, 10 remember there are four 2's, 4's, 6's,8's and 10's) = 20

Explanation

4/52 + 20/52 = 24/52 which reduces to 6/13
number of queens = 4, number of even (2, 4, 6, 8, 10 remember there are four 2's, 4's, 6's,8's and 10's) = 20