There are 7 students in a class: 5 boys and 2 girls. If the teacher picks a group of 4 at random, what is the probability that everyone in the group is a boy?

Question

There are 7 students in a class: 5 boys and 2 girls. If the teacher picks a group of 4 at random, what is the probability that everyone in the group is a boy?

Answer 1

# ways to choose 4 boys is 5C4, which has the value 5.

# ways to choose 4 persons, either gender, is 7C4.

 

P(all 4 boys chosen) = 5 / the above answer (7C4).