document.write( "Question 977489: You will purchase some CDs and DVDs. If you purchase 6 CDs and 5 DVDs, it will cost you $80.85 ; if you purchase 5 CDs and 6 DVDs, it will cost you $84.15. How much does each CD cost and how much does each DVD cost? \n" ); document.write( "

Algebra.Com's Answer #599073 by Cromlix(4381) $\"\"$ $\"About$

You can put this solution on YOUR website!
Hi there,
\n" ); document.write( "Make CDs = x
\n" ); document.write( "and DVDs = y.
\n" ); document.write( "Form two equations:-
\n" ); document.write( "6x + 5y = 80.85......(1)
\n" ); document.write( "5x + 6y = 84.15......(2)
\n" ); document.write( "Multiply (1) by 6
\n" ); document.write( "Multiply (2) by 5
\n" ); document.write( "36x + 30y = 485.1.....(1)
\n" ); document.write( "25x + 30y = 420.75....(2)
\n" ); document.write( "Subtract (2) from (1)
\n" ); document.write( "11x = 64.35
\n" ); document.write( "x = 5.85
\n" ); document.write( "Substitute x = 5.85
\n" ); document.write( "into (2)
\n" ); document.write( "5x + 6y = 84.15
\n" ); document.write( "5(5.85) + 6y = 84.15
\n" ); document.write( "29.25 + 6y = 84.15
\n" ); document.write( "........6y = 84.15 - 29.25
\n" ); document.write( "........6y = 54.90
\n" ); document.write( ".........y = 9.15
\n" ); document.write( "CD costs $5.85
\n" ); document.write( "DVD costs $9.15
\n" ); document.write( "Hope this helps:-) \n" ); document.write( "

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