Question 846562
Base case: 20 cents is doable with 2 dimes.


Assume 5k cents is doable where k >= 4. To make 5k+5 cents we can either replace two dimes with a quarter, or replace a quarter with three dimes. Since we must have either two dimes or a quarter (or both), one of the scenarios is possible, and hence we can make 5k+5 cents.