Question

Problem

There are 7 students in a class: 2 boys and 5 girls.
If the teacher picks a group of 3 at random, what is the probability that everyone in the group is a girl?

Answer 1

2/7

Explanation:

The total number of possibilities is 7 * 6 * 5

The number of possibilities for all girls is 5 * 4 * 3

so the probability is:

`(5*4*3)/(7*6*5) \\(4*3)/(7*6) \\(12)/(42) = (2)/(7)`