A bookcase contains 2 statistics books and 5 biology books. if 2 books are chosen at random, the chance that both are statistics books is

The answer is 1/15.
number of ways to choose any 2 books out of 5 biology books =⁵C₂ = 5!(2! x 3!) =10
number of ways to choose 2 statistic books out of 2 = ²C₂ = 1
So, probability that both two books are statistics books = 1/10