document.write( "Question 352481: A biker rides 106 miles in 6 hours against the wind. He rides 126 miles in 6 hours with the wind at his back. What is the speed of the wind? \n" ); document.write( "

Algebra.Com's Answer #251904 by robertb(5830) $\"\"$ $\"About$

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Let b = speed of the biker
\n" ); document.write( "w = speed of the wind.
\n" ); document.write( "This means b - w = speed of the biker relative to, and against, the wind
\n" ); document.write( "Because $\"d+=+r%2At\"$ , we get $\"6%2A%28b-w%29=106\"$ , or $\"b-w=53%2F3\"$ .
\n" ); document.write( "Also, b + w = speed of the biker relative to, and in the same direction as, the wind. So
\n" ); document.write( " $\"6%2A%28b%2Bw%29=126\"$ , or $\"b%2Bw=21\"$ . So we have the system
\n" ); document.write( " $\"b-w=53%2F3\"$ , and
\n" ); document.write( " $\"b%2Bw=21\"$ .
\n" ); document.write( "Solving this by elimination gives
\n" ); document.write( " $\"b=58%2F3\"$ and $\"w=5%2F3\"$ .
\n" ); document.write( "Therefore the speed of the wind is 5/3 miles per hour. \n" ); document.write( "

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