math
posted by quan .
you have several coins that total 38 cents. you have the same number of pennies as you do nickles. how many coins do you have?

Since the number of nickels (5 cents) is the same number as pennies (1 cent), their sum goes in multiples of 6 cents.
Assume there are N of each of pennies and nickels
N amount left
1 32
2 26
3 20
4 14
5 8
6 2
Since 20 cents equals two dimes (10 cents), we conclude that there are
2 dimes
3 nickels
3 pennies.