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 Making Change at the Boutique Shop
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In the Boutique Shop, you must determine the change a customer receives from $5.00 for each purchase and decide what coins you use to make the change.  You have quarters, dimes, nickels, and pennies. Limit: 9 of any one coin.

  • List all the different ways you can make change in this problem. Use a spreadsheet template or create your own. (1)
  •  (There are 27 ways. Here is the list.)
  • What is the least number of coins you need to find this change? (6)
  • Whats the most number of coins you can use to find this change if you have a limit of 9 of any particular coin? (19)
  • Why can you use only 8 pennies or 3 pennies? (Why not 9, 7, 6, 5, 4, 2, 1, or 0?) Try some of the numbers in parenthesis and see what happens. For example, if you have 9 pennies, then you have to make $.69 with the remaining coins. How do you make $.69 with only quarters, dimes and nickels? The amount that you make with the combinations of these three coins has to be a multiple of 5. So if you subtract the number of pennies from your required change, then the result has to be a multiple of 5.
   

  Original Copyright all rights reserved 2007. Stevens Institute of Technology.
The Center for Innovation in Engineering & Science Education
Revised: Ihor Charischak (2019)