document.write( "Question 686876: Twin brothers, person A and person B can mow their parents lawn together in 72 minutes. Person B could mow the lawn by himself in 17 minutes more than it would take person A. How long would it take each alone? The person who can solve this right first I will buy them lunch. \n" ); document.write( "
Algebra.Com's Answer #424925 by lwsshak3(11628)\"\" \"About 
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Twin brothers, person A and person B can mow their parents lawn together in 72 minutes. Person B could mow the lawn by himself in 17 minutes more than it would take person A. How long would it take each alone?
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\n" ); document.write( "let x=time it takes person A to mow the lawn alone
\n" ); document.write( "his work rate=1/x
\n" ); document.write( "x+17=time it takes person B to mow the lawn alone
\n" ); document.write( "his work rate=1/(x+17)
\n" ); document.write( "72 minutes=time it takes persons A and B to mow the lawn together
\n" ); document.write( "their work rate=1/72
\n" ); document.write( "sum of individual work rates=work rate working together
\n" ); document.write( "1/x+1/(x+17)=1/72
\n" ); document.write( "LCD:72x(x+17)
\n" ); document.write( "72(x+17)+72x=x(x+17)
\n" ); document.write( "72x+1224+72x=x^2+17x
\n" ); document.write( "144x+1224=x^2+17x
\n" ); document.write( "x^2-127x-1224=0
\n" ); document.write( "factor:
\n" ); document.write( "(x+9)(x-136)=0
\n" ); document.write( "x=-9(reject)
\n" ); document.write( "or
\n" ); document.write( "x=136
\n" ); document.write( "x+17=153
\n" ); document.write( "...
\n" ); document.write( "time it takes person A to mow the lawn alone=136 min
\n" ); document.write( "time it takes person B to mow the lawn alone=153 min
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