document.write( "Question 539550: A plane left an airport and flew with the wind for 3 hours, covering 1200 miles. It then returned over the same route to the airport against the wind in 4 hours. Find the rate of the plane in still air and the speed of the wind.\r
\n" ); document.write( "\n" ); document.write( "write steps please! thanks. \n" ); document.write( "
Algebra.Com's Answer #353459 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Plane speed =x mph
\n" ); document.write( "Wind speed =y mph
\n" ); document.write( "against wind x-y 4.00 hours
\n" ); document.write( "with wind x+y 3.00 hours
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\n" ); document.write( "Distance = same= 1200 miles
\n" ); document.write( "t=d/r
\n" ); document.write( "1200 / ( x - y )= 4.00
\n" ); document.write( "4 ( x - y ) = 1,200.00
\n" ); document.write( "4 x -4 y = 1200 ....................1
\n" ); document.write( "1200 / ( x + y )= 3.00
\n" ); document.write( "3.00 ( x + y ) = 1200
\n" ); document.write( "3.00 x + 3.00 y = 1200 ...............2
\n" ); document.write( "Multiply (1) by 3.00
\n" ); document.write( "Multiply (2) by 4.00
\n" ); document.write( "we get
\n" ); document.write( "12 x + -12 y = 3600
\n" ); document.write( "12 x + 12 y = 4800
\n" ); document.write( "24 x = 8400
\n" ); document.write( "/ 24
\n" ); document.write( "x = 350 mph
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\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "4 x -4 y = 1200
\n" ); document.write( "1400 -4 y = 1200
\n" ); document.write( "-4 y = 1200 -1400
\n" ); document.write( "-4 y = -200
\n" ); document.write( " y = 50 mph
\n" ); document.write( " Plane 350 mph
\n" ); document.write( " Wind 50 mph \r
\n" ); document.write( "\n" ); document.write( "m.ananth@hotmail.ca
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