Question

There are 99 students in a class: 77 boys and 22 girls. If the teacher picks a group of 33 at random, what is the probability that everyone in the group is a boy?

A. 77/ 99
B. 77/ 33
C. 33 /99
D. 77/3

Answer 1

To find the probability that everyone in the group is a boy, calculate the number of ways to select 33 boys from a group of 77 and divide it by the total number of ways to select 33 students from a group of 99.

Step-by-step explanation:

To find the probability that everyone in the group is a boy, we need to calculate the number of ways to select 33 boys from a group of 77 and divide it by the total number of ways to select 33 students from a group of 99.

The number of ways to select 33 boys from a group of 77 is represented by the combination formula, written as C(77, 33). The total number of ways to select 33 students from a group of 99 is represented by the combination formula, written as C(99, 33).

The probability can be calculated as C(77, 33) / C(99, 33) = 0.000080997.