Question

There are 10 students in a class: 6 boys and 4 girls.

If the teacher picks a group of 3 at random, what is the probability that everyone in the group is a boy?

Answer 1

1/6

Explanation:

Think of drawing 1 student at a time without replacement.

First drawing:

p(boy) = 6/10

Second drawing:

p(boy) = 5/9

Third drawing:

p(boy) = 4/8

p(3 boys) = 6/10 * 5/9 * 4/8 = 3/5 * 5/9 * 1/2 = 3/18 = 1/6

Answer: 1/6

Answer 2

1/ 6

Explanation:

Therefore, the required probability is 1/6.