document.write( "Question 933517: Find the number of nickels, dimes, and quarters in a collection of 80 such coins if the nickels and the quarters are worth $4.50 and the value of the quarters and the dimes is $5.50.\r
\n" ); document.write( "\n" ); document.write( "My work:
\n" ); document.write( ".5n + .25q = 4.50
\n" ); document.write( ".10d + .25q = 5.50
\n" ); document.write( ".10d - .5n = 1.00\r
\n" ); document.write( "\n" ); document.write( "n + .5q = 9
\n" ); document.write( "d + 2.5q = 55
\n" ); document.write( "d - 5n = 10
\n" ); document.write( "d + n + q = 80 coins\r
\n" ); document.write( "\n" ); document.write( "Ive tried everything, even made a chart - please help!! \n" ); document.write( "
Algebra.Com's Answer #566851 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
Find the number of nickels, dimes, and quarters in a collection of 80 such coins if the nickels and the quarters are worth $4.50 and the value of the quarters and the dimes is $5.50.
\n" ); document.write( "------
\n" ); document.write( "Quantity:: n + d + q = 80 coins
\n" ); document.write( "Value:: 5n + 25q = 450 cents
\n" ); document.write( "Value:: 10d + 25q = 550 cents
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\n" ); document.write( "Using the bottom 2 equations,
\n" ); document.write( "Subtract and solve for 10d-5n::
\n" ); document.write( "10d-5n = 100
\n" ); document.write( "Modify::
\n" ); document.write( "2d - n = 20
\n" ); document.write( "n = 2d-20
\n" ); document.write( "---
\n" ); document.write( "Substitute for \"n\" in equation #1 to get::
\n" ); document.write( "2d-20 + d + q = 80
\n" ); document.write( "3d + q = 100
\n" ); document.write( "q = -3d+100
\n" ); document.write( "----
\n" ); document.write( "Substitute for \"n\" and for \"q\" in 5n+25q=450 to solve for \"d\"
\n" ); document.write( "5(2d-20) + 25(-3d+100) = 450
\n" ); document.write( "10d - 100 -75d + 2500 = 450
\n" ); document.write( "-65d = 450-2400
\n" ); document.write( "-65d = -1950
\n" ); document.write( "d = 30 (# of dimes)
\n" ); document.write( "----
\n" ); document.write( "Solve for \"q\" using q = -3d+100
\n" ); document.write( "q = -3*30+100 = 10 (# of quarters)
\n" ); document.write( "----
\n" ); document.write( "Solve for \"n\" using n = 2d-20
\n" ); document.write( "n = 2*30-20 = 40 (# of quarters)
\n" ); document.write( "----
\n" ); document.write( "Checking with the 1st equation:
\n" ); document.write( "30 + 10 + 40 = 80 coins
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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