document.write( "Question 223774: The perimeter of a rectangle is 60cm. If the length is decreased by 5 and the width is halved, the perimeter will decrease by 20cm. What are the length and width of the original rectangle? \n" ); document.write( "
Algebra.Com's Answer #167270 by drj(1380)\"\" \"About 
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The perimeter of a rectangle is 60cm. If the length is decreased by 5 and the width is halved, the perimeter will decrease by 20cm. What are the length and width of the original rectangle?\r
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\n" ); document.write( "\n" ); document.write( "Step 1. Perimeter P means adding up all 4 sides of a rectangle.\r
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\n" ); document.write( "\n" ); document.write( "Step 2. Let w be the original width.\r
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\n" ); document.write( "\n" ); document.write( "Step 3. Let L be the original length.\r
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\n" ); document.write( "\n" ); document.write( "Step 4. Let w/2 be the width cut in half\r
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\n" ); document.write( "\n" ); document.write( "Step 5. Let L-5 be the length reduced by 5\r
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\n" ); document.write( "\n" ); document.write( "Step 6. Then, original perimeter P0=L+L+w+w=2L+2w=60\r
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\n" ); document.write( "\n" ); document.write( "Step 7. Then, new perimeter \"P1=L-5%2BL-5%2Bw%2F2%2Bw%2F2=2L%2Bw-10=60-20=40\" or \"2L%2Bw=50\" after adding 10 to both sides.\r
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\n" ); document.write( "\n" ); document.write( "Step 8. Our linear system of equation is given in Steps 6 and 7 as\r
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\n" ); document.write( "\n" ); document.write( "\"2L%2B2w=60\"\r
\n" ); document.write( "\n" ); document.write( "\"2L%2Bw=50\"\r
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
\n" ); document.write( " \"+system%28+%0D%0A++++2%5CL+%2B+2%5Cw+=+60%2C%0D%0A++++2%5CL+%2B+1%5Cw+=+50+%29%0D%0A++\"We'll use substitution. After moving 2*w to the right, we get:
\n" ); document.write( " \"2%2AL+=+60+-+2%2Aw\", or \"L+=+60%2F2+-+2%2Aw%2F2\". Substitute that
\n" ); document.write( " into another equation:
\n" ); document.write( " \"2%2A%2860%2F2+-+2%2Aw%2F2%29+%2B+1%5Cw+=+50\" and simplify: So, we know that w=10. Since \"L+=+60%2F2+-+2%2Aw%2F2\", L=20.
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\n" ); document.write( " Answer: \"system%28+L=20%2C+w=10+%29\".
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\n" ); document.write( "\n" ); document.write( "With \"L=20\" and \"w=10\". And \"P0=2%2820%2B10%29=60\" and \"P1=+2%2A20%2B10-10=40\" which are true statements.\r
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\n" ); document.write( "\n" ); document.write( "Step 5. ANSWER: The width is 10 cm and the length is 20 cm.\r
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\n" ); document.write( "\n" ); document.write( "I hope the above steps were helpful.\r
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\n" ); document.write( "\n" ); document.write( "For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.\r
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\n" ); document.write( "\n" ); document.write( "Good luck in your studies!\r
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\n" ); document.write( "\n" ); document.write( "Respectfully,
\n" ); document.write( "Dr J
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