document.write( "Question 1164594: Flying against the wind, an airplane travels 3060 kilometers in 6 hours. Flying with the wind, the same plane travels 7070 kilometers in 7 hours. What is the rate of the plane in still air and what is the rate of the wind? \n" ); document.write( "

Algebra.Com's Answer #789011 by ikleyn(52866) $\"\"$ $\"About$

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document.write( "Let \"u\" be the plane speed in still air;  \"v\" be the speed of the wind.\r\n" );
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document.write( "Then from the condition, effective rate with the wind is\r\n" );
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document.write( "    u + v =  = 1010  km/h\r\n" );
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document.write( "Effective rate against the wind is\r\n" );
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document.write( "     u -v =  = 510  km/h\r\n" );
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document.write( "Add the two equations  (1)  and  (2)  to get\r\n" );
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document.write( "    2u    = 1520;  \r\n" );
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document.write( "     u    = 1520/2 = 760.\r\n" );
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document.write( "Then from equation (1),\r\n" );
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document.write( "     v    = 1010 - 760 = 250.\r\n" );
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document.write( "ANSWER.  The plane speed in the still air is  760 km/h.  The wind speed is 250 km/h.\r\n" );
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