8MM Probability Quiz

From a pack of 52 cards, one card is drawn at random. Find the probability of drawing a king.

Answer explanation

There are 4 kings in a standard deck of cards. Therefore,

Pr(King) = 4/52 = 1/13

A bag contains 4 white, 3 red and 2 black balls. If a ball is drawn at random, find the probability that it is not white.

Answer explanation

Number of not white marbles = 2 + 3 = 5
Pr (White') = 5/9
OR
Pr(White') = 1 - Pr(white)
= 1 - 4/9
= 5/9

From a pack of 52 playing cards, a card is chosen at random. What is the probability that it is a red Queen or a 4?

Answer explanation

There are 2 red Queens and 4 fours = 6

Pr(Queen OR four) = 6/52 = 3/26

Two dice are thrown. Find the probability that the sum is less than 5.

Answer explanation

Sum is less than 5 for the rolls:

(1, 1), (1, 2), (1, 3), (2, 1), (2, 2), (3, 1)

Pr(Sum < 5) = 6/36 = 1/6

A drawer contains 13 black socks, 14 white socks and 8 grey socks. If one sock is selected at random, what is the probability that it is not black?

Answer explanation

Pr(Black') = 1 - Pr(Black)
= 1 - 13/35
= 22/35

This Venn diagram displays Year 8 students' mode of transport to school one morning. How many students travelled on a bus?

• 42

• 25

• 15

• 67

Answer explanation

42 students took ONLY the bus and 25 took the bus AND train

Total = 42 + 25 = 67 took the bus

What is the probability that a student did not travel by bus to school that day?

Answer explanation

Students who did not take the bus = 13 + 15 = 28

Pr(Bus') = 28/95

This two way table shows a group of year 8 students at a particular school. How many female students play an instrument?

• 32

• 22

• 54

• 21

Answer explanation

54 - 32 = 22

If one student is selected randomly, what is the probability that it is a female who doesn't play an instrument?

Answer explanation

Number of females who don't play an instrument = 21

Pr (F doesn't play an instrument) = 21/90 = 7/30

If a male student is selected at random, what is the probability that he plays an instrument?