document.write( "Question 231857: An airplane travels 400 miles against the wind in 5 hours, and makes the return trip with the same wind in 2hours. Find the speed of the wind. \n" ); document.write( "
Algebra.Com's Answer #171489 by stanbon(75887)\"\" \"About 
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An airplane travels 400 miles against the wind in 5 hours, and makes the return trip with the same wind in 2hours. Find the speed of the wind.
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\n" ); document.write( "Against the wind DATA:
\n" ); document.write( "distance = 400 miles ; time = 5 hrs ; rate = 400/5 = 80 mph
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\n" ); document.write( "With the wind DATA:
\n" ); document.write( "distance = 400 miles ; time = 2 hrs ; rate = 400/2 = 200 mph
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\n" ); document.write( "Equations:
\n" ); document.write( "Let \"p\" be speed of the plane in still air
\n" ); document.write( "Let \"w\" be speed of the wind
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\n" ); document.write( "p + w = 200
\n" ); document.write( "P - w = 80
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\n" ); document.write( "Add the two equations to solve for \"p\":
\n" ); document.write( "2p = 280
\n" ); document.write( "p = 140 mph (speed of the plane in still air)
\n" ); document.write( "---Substitute into P+w = 200 to solve for \"w\"
\n" ); document.write( "140 + w = 200
\n" ); document.write( "w = 60 mph (speed of the wind)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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