document.write( "Question 498946: A jet makes a trip to the maintenance facility and back. The trip there took 9 hours and the trip back took 6 hours. It averaged 330 km/h on the return trip. Find the average speed of the trip there. \n" ); document.write( "
Algebra.Com's Answer #337370 by mananth(16949)\"\" \"About 
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Plane speed =x mph
\n" ); document.write( "Wind speed =y mph
\n" ); document.write( "against wind x-y 18.00 hours
\n" ); document.write( "with windx+y 9.00 hours
\n" ); document.write( "
\n" ); document.write( "Distance = same= 864 miles
\n" ); document.write( "t=d/r
\n" ); document.write( "864/(x- y)=18.00
\n" ); document.write( "18(x-y)=864.00
\n" ); document.write( "18x-18y =864 ....................1
\n" ); document.write( "864/(x+y)= 9.00
\n" ); document.write( "9.00(x+y)= 864
\n" ); document.write( "9.00 x + 9.00 y = 864 ...............2
\n" ); document.write( "Multiply (1) by 1.00
\n" ); document.write( "Multiply (2) by 2.00
\n" ); document.write( "we get
\n" ); document.write( "18 x + -18 y = 864
\n" ); document.write( "18 x + 18 y = 1728
\n" ); document.write( "add the two
\n" ); document.write( "36 x = 2592
\n" ); document.write( "/ 36
\n" ); document.write( "x = 72 mph
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "18 x -18 y = 864
\n" ); document.write( "1296 -18 y = 864
\n" ); document.write( "-18 y = 864 -1296
\n" ); document.write( "-18 y = -432
\n" ); document.write( " y = 24 mph
\n" ); document.write( " \n" ); document.write( "
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