document.write( "Question 176170: Question: A heating and ventilation engineer purchases four 1m radiators and three 1.5m radiators at a cost of Ł159 for a project. In addition he purchases five 1m radiators and two 1.5m radiators at a cost of Ł134. Determine the cost of both types of radiator. \n" ); document.write( "

Algebra.Com's Answer #131261 by Mathtut(3670) $\"\"$ $\"About$

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lets call the cost of 1m and 1.5m radiators, r and s , respectively
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\n" ); document.write( "4r+3s=159.....eq 1
\n" ); document.write( "5r+2s=134.....eq 2
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\n" ); document.write( "multiply eq 1 by 2 and eq 2 by -3
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\n" ); document.write( "::8r+6s=318....eq 1 revised
\n" ); document.write( "-15r-6s=-402....eq 2 revised
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\n" ); document.write( " add the two equations together. as you can observe the s terms are eliminated because 6s-6s=0. We are left with 8r-15r=318-402.
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\n" ); document.write( "-7r=-84
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\n" ); document.write( " $\"highlight%28r=12%29\"$ per 1m radiator
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\n" ); document.write( "now plug the value of r just found into any of the equations. I choose eq 1
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\n" ); document.write( "4(12)+3s=159--->3s=111
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\n" ); document.write( " $\"highlight%28s=37%29\"$ per 1.5m radiator \n" ); document.write( "

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