document.write( "Question 1197131: It took a bird the same amount of time to fly 10 miles with wind as 5 miles against the wind. What is the speed of the wind if the bird flies 30 mph in still air? \n" ); document.write( "
Algebra.Com's Answer #830254 by ikleyn(52794)\"\" \"About 
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document.write( "Let w be the rate of the wind.\r\n" );
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document.write( "Write the \"time\" equation as you read the problem\r\n" );
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document.write( "    \"10%2F%2830%2Bw%29\" = \"5%2F%2830-w%29\".\r\n" );
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document.write( "Here 30+w is the effective speed with the wind \r\n" );
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document.write( "and \"10%2F%2830%2Bw%29\" is the time to fly 10 miles with the wind,\r\n" );
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document.write( "so it explains left side of the equation.\r\n" );
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document.write( "Right side describes the time flying 5 miles against the wind.\r\n" );
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document.write( "From this equation, by cross-multiplying, you get\r\n" );
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document.write( "    10*(30-w) = 5*(30+w)\r\n" );
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document.write( "    300 - 10w = 150 + 5w\r\n" );
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document.write( "    300 - 150 = 10w + 5w\r\n" );
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document.write( "       150    =    15w\r\n" );
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document.write( "         w    =    150/15 = 10 miles per hour.    ANSWER\r\n" );
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