document.write( "Question 210136: a plane flies with a ground speed of 160 miles per hour if there is no wind. it travels 350 miles with a head wind and in the same time it takes to go 450miles with a tail wind.find the speed of the wind. \n" ); document.write( "
Algebra.Com's Answer #158857 by ankor@dixie-net.com(22740)\"\" \"About 
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a plane flies with a ground speed of 160 miles per hour if there is no wind.
\n" ); document.write( " it travels 350 miles with a head wind and in the same time it takes to go 450
\n" ); document.write( " miles with a tail wind.
\n" ); document.write( "find the speed of the wind.
\n" ); document.write( ":
\n" ); document.write( "Let w = wind speed
\n" ); document.write( "then
\n" ); document.write( "(160+w) = speed with the wind
\n" ); document.write( "and
\n" ); document.write( "(160-w) = speed against the wind
\n" ); document.write( ":
\n" ); document.write( "They fly the two distances in equal times. Write a time equation; Time = \"dist%2Fspeed\"
\n" ); document.write( "Time against = Time with
\n" ); document.write( "\"350%2F%28%28160-w%29%29\" = \"450%2F%28%28160%2Bw%29%29\"
\n" ); document.write( "Cross multiply
\n" ); document.write( "350(160+w) = 450(160-w)
\n" ); document.write( ":
\n" ); document.write( "56000 + 350w = 72000 - 450w
\n" ); document.write( ":
\n" ); document.write( "350w + 450w = 72000 - 56000
\n" ); document.write( ":
\n" ); document.write( "800w = 16000
\n" ); document.write( "w = \"16000%2F800\"
\n" ); document.write( "w = 20 mph wind
\n" ); document.write( ";
\n" ); document.write( ":
\n" ); document.write( "Check solution, find the time, (they should be equal):
\n" ); document.write( "450/180 = 2.5 hrs
\n" ); document.write( "350/140 = 2.5 hrs\r
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