document.write( "Question 719418: A pilot can fly a plane at 75 mph in calm air. A recent trip of 300 mi flying with the wind and 300 mi returning against the wind took 9 h. Find the rate of the wind. \n" ); document.write( "
Algebra.Com's Answer #441345 by mananth(16946)\"\" \"About 
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Plane speed = 75 mph
\n" ); document.write( "wind speed = x mph
\n" ); document.write( " 0.60
\n" ); document.write( "against current = 75 - x
\n" ); document.write( "with current = 75 + x
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\n" ); document.write( "Total distance = 300 miles Total Time= 9.00 hours
\n" ); document.write( "Time upstream + time downstream =
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\n" ); document.write( "300 /( 75 - x )+ 300 /( 75 + x )= 9
\n" ); document.write( "300 ( 75 + x )+ 300 ( 75 - x )= 9.00 ( 5625 - 1 X^2 )
\n" ); document.write( "22500 + 300 x + 22500 -300 x = 50625 - 9 X^2
\n" ); document.write( "45000 - -50625 = -9 X^2
\n" ); document.write( "-5625 = -9 X^2
\n" ); document.write( "-9 X^2= -5625
\n" ); document.write( "X^2 = 625
\n" ); document.write( "X = +/- 25
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\n" ); document.write( "wind speed 25 mph
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