Question 855412: When handing back your $9 in change, the cashier realized she had no more one dollar bills left, and had to give you the final $2 all in coins. If she handed you 27 coins, none of which were dollar or half-dollar coins, what is the greatest number of pennies she could have handed you?
Answer by JulietG(1812)   (Show Source):
You can put this solution on YOUR website! Possibilities are quarters (.25), dimes (.10), nickels (.05) and pennies (.01).
Since we only want to find the maximum number of pennies, it's much easier.
27 coins total.
Start with the quarters to get as close as possible to 2.00 since we're after the maximum amount of pennies.
7 * .25 = 1.75
Can you make .25 with 20 coins? Not possible.
What if you used 6 quarters? Then you'll need .50 with 21 coins. Remembering that we're looking for the greatest number of pennies, we'll try 15 (we can see right off that 20 won't work, and the number ends in .00 so we need a multiple of 5).
6 quarters + 15 pennies = 1.65 using 21 coins
Is it possible to make .35 with the remaining 6 coins?
Yes it is. I'll leave you to figure out how :-) [hint: use 1 of 1 coin]
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Maximum pennies = 15
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