Question

Of students at a particular university: 20% are freshmen 22% are sophomores 23% are juniors 28% are seniors 7% are graduate students. Additionally, 60% of students are female. You may assume that being female is independent of the above classifications. If we select students, one at a time, stopping once a female student is selected, what is the probability we will select 2 or fewer students?

Answer 1

Let

X: The number of students selected after stopping the selction

P(female students)=0.6

To find

We stop when a female student is selected so in case of P(X=1) we need to select a female student itself

In case of P(X=2) first student would not be a female and 2nd would be female

So

so the probability we select two or fewer students is 0.84