document.write( "Question 187325: 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 50-cent piece. There are 30 coins in all. How many of each kind are there? \n" ); document.write( "

Algebra.Com's Answer #140417 by stanbon(75887) $\"\"$ $\"About$

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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 50-cent piece. There are 30 coins in all. How many of each kind are there?
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\n" ); document.write( "Change = 20 - 9.25 = $10.75
\n" ); document.write( "-----------------------------
\n" ); document.write( "Equations:
\n" ); document.write( "Quantity Equation: q + f = 30
\n" ); document.write( "Value Equation:..25q +50f= 1075
\n" ); document.write( "-------------------------------------
\n" ); document.write( "Modify to set up for elimination:
\n" ); document.write( "25q + 25f = 25*30
\n" ); document.write( "25q + 50f = 1075
\n" ); document.write( "----------------------
\n" ); document.write( "Subtract 1st equation from the 2nd to solve for \"f\":
\n" ); document.write( "25f = 325
\n" ); document.write( "f = 13 (# of fifty-cent pieces)
\n" ); document.write( "---
\n" ); document.write( "Substitute to solve for \"q\":
\n" ); document.write( "q + 13 = 30
\n" ); document.write( "q = 17 (# of quarters)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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