document.write( "Question 703514: a plane can fly 4800km in 4h with the wind. the return trip against the same wind takes 5h. find the rate of the plane in the still air and the rate of the wind. please shows steps thank you \n" ); document.write( "

Algebra.Com's Answer #433529 by mananth(16949) $\"\"$ $\"About$

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Plane speed =x mph
\n" ); document.write( "wind speed =y mph
\n" ); document.write( "against wind 5 hours
\n" ); document.write( "with wind 4 hours
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\n" ); document.write( "Distance with wind 4800 miles distance against wind 4800
\n" ); document.write( "t=d/r against wind (x-y)
\n" ); document.write( "4800.00 / ( x - y )= 5.00
\n" ); document.write( "
\n" ); document.write( "5.00 x - -5.00 y = 4800.00 ....................1
\n" ); document.write( "with wind (x+y)
\n" ); document.write( "4800.00 / ( x + y )= 4.00
\n" ); document.write( "4.00 ( x + y ) = 4800.00
\n" ); document.write( "4.00 x + 4.00 y = 4800.00 ...............2
\n" ); document.write( "Multiply (1) by 4.00
\n" ); document.write( "Multiply (2) by 5.00
\n" ); document.write( "we get 2.00
\n" ); document.write( "20.00 x + -20.00 y = 19200.00
\n" ); document.write( "20.00 x + 20.00 y = 24000.00
\n" ); document.write( "40.00 x = 43200.00
\n" ); document.write( "/ 40.00
\n" ); document.write( "x = 1080 mph
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\n" ); document.write( "plug value of x in (1) y
\n" ); document.write( "5 x -5 y = 4800
\n" ); document.write( "5400 -5 -5400 = 4800
\n" ); document.write( "-5 y = 4800
\n" ); document.write( "-5 y = -600 mph
\n" ); document.write( " y = 120
\n" ); document.write( "Plane 1080 mph
\n" ); document.write( "wind 120 mph
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "x+y= 1200
\n" ); document.write( "X-y= 960 +
\n" ); document.write( "4800.00 / ( 1200.00 )= 4
\n" ); document.write( "4800 / ( 960 ) = 5
\n" ); document.write( " \n" ); document.write( "

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