document.write( "Question 65322: an airplane flies 1449 miles against the wind and 1539 miles with the wind in a total time of 5hours. the speed of the airplane in still air is 600mph. what is the speed of the wind ? \n" ); document.write( "
Algebra.Com's Answer #45859 by stanbon(75887)\"\" \"About 
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an airplane flies 1449 miles against the wind and 1539 miles with the wind in a total time of 5hours. the speed of the airplane in still air is 600mph. what is the speed of the wind ?
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\n" ); document.write( "Let \"w\" be the speed of the wind.
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\n" ); document.write( "Against the wind DATA:
\n" ); document.write( "distance=1449 miles ; rate= 600-w mph ; time= d/r = 1449/(600-w) hrs
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\n" ); document.write( "With the wind DATA:
\n" ); document.write( "distance=1539 miles ; rate=(600 + w) mph ; time= d/r = 1539/(600+w) hrs
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\n" ); document.write( "EQUATION:
\n" ); document.write( "time out + time back = 5 hrs
\n" ); document.write( "1449/(600-w) + 1539/(600+w) = 5 hrs
\n" ); document.write( "1449(600+w)+1539(600-w)=5(600^2-w^2)
\n" ); document.write( "1792800-90w=1800000-5w^2
\n" ); document.write( "5w^2-90w-7200=0
\n" ); document.write( "w^2-18w-1440=0
\n" ); document.write( "(w-48)(x+30)=0
\n" ); document.write( "w=48 mph (speed of the wind)
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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