A graduate class consist of six students. what is the probability that exactly three of then are born in either in april or in october?

Answer 1

the size of the class does not matter. Assuming a random population,

P(April)=P(Oct) = 1/12

P of 3 students all in same month is thus (1/12)^3

Given two months, p is twice that.

so, the probability here is 2*(1/12)^3