SOLUTION: Christina makes a $9.25 purchase at a bookstore in Reno with a $20 bill. The store has no bills and gives her the change in quarters and fifty cent pieces. There are 30 coins in al

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Question 182833: Christina makes a $9.25 purchase at a bookstore in Reno with a $20 bill. The store has no bills and gives her the change in quarters and fifty cent pieces. There are 30 coins in all. How many of each kind are there?
Answer by solver91311(24713) About Me  (Show Source):
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The amount of change was . Easier to use whole numbers so change that to 1175 cents.

Let q be the number of quarters and f be the number of half-dollars. Since there were 30 coins:



The value of the quarters is 25 cents times the number of quarters, or . Likewise, the value of the half-dollars is .

The value of the quarters plus the value of the half-dollars must total the amount of change, or 1175 cents.



Substitute from the earlier relationship:



Solve for q to get the number of quarters, subtract from 30 to get the number of half-dollars.


John