the complete question in the attached figure
we know that
The probability on the first day is 3/5 since there are 3 novels out of 5 and when you take a book out at random, all of them have a equal chance of being picked. Since you returned the book to the bag, the next day too, we have the same probability.
Probability of a novel being grabbed both days is the product of the two probabilities-----> (3/5)*(3/5)----> 9/25
the answer is
9/25