SOLUTION: Mary Kay has 15 coins that total $1.00. What are the coins and how many of each does she have? There is more than one answer.

I count 9 ways.  She has to use either no pennies, 
5 pennies or 10 pennies.

There are 2 ways to use no pennies:

If you don't use quarters, 5 dimes and 10 pennies 
If you use 1 quarter, you can make the remaining 75 cents only with
1 dime and 13 nickels.

There are 4 ways to use 5 pennies, (making 95 cents with 10 other coins):

9 dimes,1 nickel and 5 pennies.
1 quarter, 5 dimes, 4 nickels and 5 pennies.
2 quarters, 1 dime, 7 nickels and 5 pennies.
1 half dollar, 9 nickels and 5 pennies.

There are 3 ways to use 10 pennies (making 90 cents with 5 other coins):

3 quarters, 1 dime, 1 nickel and 10 pennies.
1 half dollar, 4 dimes and 10 pennies.
1 half dollar, 1 quarter, 3 nickels and 10 pennies.

Edwin