document.write( "Question 299199: An airplane took 4 hours to fly 1200 miles agianst a headwind.The return trip with the wind took 3 hours. Find the speed of the plane in still air and the speed of the wind. What is the speed of the wind in still air? What is the wind speed? \n" ); document.write( "
Algebra.Com's Answer #215073 by mananth(16946)\"\" \"About 
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An airplane took 4 hours to fly 1200 miles agianst a headwind.The return trip with the wind took 3 hours. Find the speed of the plane in still air and the speed of the wind. What is the speed of the wind in still air? What is the wind speed?\r
\n" ); document.write( "\n" ); document.write( "let rate of plane in still air be x
\n" ); document.write( "let rate of wind be y\r
\n" ); document.write( "\n" ); document.write( "(x-y)*4 =1200\r
\n" ); document.write( "\n" ); document.write( "(x+y)*3=1200\r
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\n" ); document.write( "\n" ); document.write( "4x-4y=1200\r
\n" ); document.write( "\n" ); document.write( "3x+3y=1200\r
\n" ); document.write( "\n" ); document.write( "3(4x-4y)+4(3x+3y)=3*1200+4*1200\r
\n" ); document.write( "\n" ); document.write( "12x-12y + 12x +12y = 8400\r
\n" ); document.write( "\n" ); document.write( "24x=8400
\n" ); document.write( "x=350 mph rate of plane in still air\r
\n" ); document.write( "\n" ); document.write( "(x+y)*3=1200
\n" ); document.write( "(350+y)*3 =1200\r
\n" ); document.write( "\n" ); document.write( "1050+3y=1200\r
\n" ); document.write( "\n" ); document.write( "3y=1200-1050\r
\n" ); document.write( "\n" ); document.write( "3y= 150\r
\n" ); document.write( "\n" ); document.write( "y=50 mph rate of wind\r
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