Penny's favorite coin is the dime. She knows she has fewer than 100 of them. One day she was arranging them on her desk in different ways. She
found that when she put them into piles of two, there was one left over.
When she put them into piles of three, there was one left over, and the
same thing happened when she put them into piles of four. She then tried
putting them into piles of five, and found that there were none left over.
How many dimes does Penny have?