math
posted by Brianna on .
How many ways can you have $1.05, with only using dimes, nickels, and quarters?

make a systematic listing of quarters, dimes and nickels to add up to $1.05, starting the the largest remaining possibility for each type of coin
Q D N
4 0 1
3 3 0
3 2 2
3 1 4
3 0 6
2 5 1
2 4 3
...
..
0 1 19
0 0 21