I assume that the choosing is done without replacement.A survey is carried out on a group of 100 students, 60 of whom are boys.
Find the probability that any 2 students chosen at random from the original group will be both girls.
There are: 60 boys and 40 girls.
There are: . possible pairs of students.
To choose 2 girls, there are: . ways.
The probability that the first student is a girl is: .
The probability that the second student is a girl is: .