document.write( "Question 103946: Rectangle of a perimeter is 240cm. If the lenght of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm) find the length & breadth of rectangle \n" ); document.write( "
Algebra.Com's Answer #75628 by ankor@dixie-net.com(22740)\"\" \"About 
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Rectangle of a perimeter is 240cm. If the length of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm) find the length & breadth of rectangle
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\n" ); document.write( "\"Rectangle of a perimeter is 240cm.\"
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\n" ); document.write( "Let x = the original length; y = original width
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\n" ); document.write( "2x + 2y = 240
\n" ); document.write( "Simplify divide equation by 2:
\n" ); document.write( "x + y = 120
\n" ); document.write( "or
\n" ); document.write( "y = (120-x); for substitution
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\n" ); document.write( "\"If the lenght of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm)\"
\n" ); document.write( "New length = .9x
\n" ); document.write( "New width = 1.2y
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\n" ); document.write( "2(.9x) + 2(1.2y) = 240
\n" ); document.write( "Simplify, divide by 2
\n" ); document.write( ".9x + 1.2y = 120
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\n" ); document.write( "\"find the length & breadth of rectangle\"
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\n" ); document.write( "Substitute(120-x) for y in the above equation, find x:
\n" ); document.write( ".9x + 1.2(120-x) = 120
\n" ); document.write( ".9x + 144 - 1.2x = 120
\n" ); document.write( ".9x - 1.2x = 120 - 144
\n" ); document.write( "-.3x = -24
\n" ); document.write( "x = -24/-.3
\n" ); document.write( "x = + 80 cm is the original length
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\n" ); document.write( "Width: 120 - 80 = 40 cm is the original width
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\n" ); document.write( "Find the new dimension:
\n" ); document.write( ".9 * 80 = 72 cm, new length
\n" ); document.write( "1.2 * 40 = 48 cm new width
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\n" ); document.write( "Check the new perimeter
\n" ); document.write( "2(72) + 2(48) =
\n" ); document.write( "144 + 96 = 240
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