Joaquin needs to make change for $0.75 using nickels, dimes, and quarters. There are several different combinations of change that he can have.
Here are all possible combination of change:
1. 3 quarters
2. 1 quarter and 1 half-dollar coin
3. 1 quarter, 1 nickel and 2 dimes
4. 1 quarter and 5 nickels
5. 3 dimes and 2 nickels
6. 15 nickels
Note that for the last question, these are all possibilities, but in real life, it may not make sense to use 15 nickels for a change of $0.75 as it would make it heavy to carry.