Please help me this is hard

Question

There are twenty books on a shelf, six Science books and fourteen History books. Each student goes up to the shelf, selects a book and brings it back to their desk. What is the probability that both books will be Science?

Answer 1

Assumption: each of 2 students select a book at random.

Probability of first student selecting a science book is 6/20.

Now there are 5 science books out of 19 books.

Then the probability of the second student selecting a science book is 5/19.

So the joint probability is (6/20) * {5/19) or about 0.079.