document.write( "Question 1134644: An airplane can travel 395mph in still air. If it travels 1242 miles with the wind in the same length of time it travels 1128 miles against the wind, what is the speed of the wind? \n" ); document.write( "
Algebra.Com's Answer #752090 by Alan3354(69443)\"\" \"About 
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An airplane can travel 395mph in still air. If it travels 1242 miles with the wind in the same length of time it travels 1128 miles against the wind, what is the speed of the wind?
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\n" ); document.write( "w = windspeed
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\n" ); document.write( "1242/(395 + w) = 1128/(395 - w)
\n" ); document.write( "Cross multiply
\n" ); document.write( "1242*(395-w) = 1128*(395+w)
\n" ); document.write( "1242*395 - 1242w = 1128*395 + 1128w
\n" ); document.write( "114*395 = 2370w
\n" ); document.write( "w = 19 mi/hr
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\n" ); document.write( "PS Planes use knots, not mi/hr
\n" ); document.write( "Boats also use knots.
\n" ); document.write( "Knots are units of speed. 1 knot = 1 nm/hr, 1 nautical mile per hour.
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\n" ); document.write( "That does not affect the answer or the calculations, but it's another example of people writing math problems who do not know the subject.
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\n" ); document.write( "Buildings and universities use mi/hr, km/hr and other units, but planes use knots.
\n" ); document.write( "No building or institution has ever filed a flight plan and left the ground.\r
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