Question

Paul owes Paula 35 cents and has a pocket full of 5-cent coins, 10-cent coins, and 25-cent coins that he can use to pay her. What is the difference between the largest and the smallest number of coins he can use to pay her?

Answer 1

The smallest number of coins is theoretically 1, a 35 cents coin. but there aren't such coins! so it must be 2, 10+25

the biggest is using 5 cent coints, with 7 different coins.

and the difference is 5 coins: 7-2=5