document.write( "Question 201088: Big plane. A six-passenger plane cruises at 180 mph in
\n" ); document.write( "calm air. If the plane flies 7 miles with the wind in the
\n" ); document.write( "same amount of time as it flies 5 miles against the wind,
\n" ); document.write( "then what is the wind speed? \n" ); document.write( "

Algebra.Com's Answer #151356 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"w\"$ = wind speed
\n" ); document.write( "Let $\"s\"$ = speed of plane in calm air
\n" ); document.write( "Let $\"t\"$ = time for both trips
\n" ); document.write( "given:
\n" ); document.write( " $\"s+=+180\"$
\n" ); document.write( "With the wind:
\n" ); document.write( " $\"7+=+%28180+%2B+w%29%2At\"$
\n" ); document.write( " $\"5+=+%28180+-+w%29%2At\"$
\n" ); document.write( "--------------------
\n" ); document.write( " $\"7+=+180t+%2B+wt\"$
\n" ); document.write( " $\"5+=+180t+-+wt\"$
\n" ); document.write( "Add the equations
\n" ); document.write( " $\"12+=+360t\"$
\n" ); document.write( " $\"t+=+1%2F30\"$ hrs
\n" ); document.write( "and, since
\n" ); document.write( " $\"5+=+%28180+-+w%29%2At\"$
\n" ); document.write( " $\"5+=+%28180+-+w%29%2A%281%2F30%29\"$
\n" ); document.write( " $\"150+=+180+-+w\"$
\n" ); document.write( " $\"w+=+180+-+150\"$
\n" ); document.write( " $\"w+=+30\"$
\n" ); document.write( "The windspeed is 30 mi/hr\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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