Question

A change machine changes dollar bills into quarters and nickels. If you receive 12 coins after inserting a dollar bill, how many nickels did you receive?

Answer 1

10 coins are nickels and 2 coins are quarters

Answer 2

Well, given that a quarter equals 5 nickels, we can reason that, in order to get 12 coins, we would have to get 10 nickels (equals 50 cents) and 2 quarters (the other 50 cents, to make a dollar).

You didn't say whether you needed this expressed in a mathematical formula, but knowing the answer already, it shouldn't be hard to come up with one if necessary.

Hope this helps.