document.write( "Question 1186288: A plane has a cruising speed of 200 miles per hour when there is no wind. At this speed, the plane flew 500 miles with the wind in the same amount of time it flew 300 miles against the wind. Find the speed of the wind.\r
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Algebra.Com's Answer #817170 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "A plane has a cruising speed of 200 miles per hour when there is no wind.
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document.write( "Let x be the speed of the wind, in miles per hour.\r\n" );
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document.write( "Then the plane's effective speed flying with the wind is (200+x) mph;\r\n" );
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document.write( "                 effective speed flying against the wind is (200-x) mph.\r\n" );
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document.write( "Now we write the \"time\" equation\r\n" );
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document.write( "     = \r\n" );
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document.write( "To solve it, first cross-multiply; then simplify and find x\r\n" );
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document.write( "    500*(200-x) = 300*(200+x)\r\n" );
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document.write( "      5*(200-x) =   3*(200+x)\r\n" );
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document.write( "    1000 - 5x   =   600 + 3x\r\n" );
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document.write( "    1000 - 600  =   3x  + 5x\r\n" );
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document.write( "        400     =     8x\r\n" );
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document.write( "         x      =  400/8 = 50.\r\n" );
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document.write( "ANSWER.  The speed of the wind is  50  miles per hour  (rounded).\r\n" );
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document.write( "CHECK.    = 2  hours with the windth.\r\n" );
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document.write( "          = 2 hours against the windth.    ! The flying time is the same:  CORRECT !\r\n" );
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