document.write( "Question 1111738: Flying against the wind, an airplane travels 3240 km in 6 hours. Flying with the wind, the same plane travels 8160 km in 8 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 #726746 by ikleyn(52876) $\"\"$ $\"About$

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document.write( "Let u = airplane speed at no wind and v = the wind speed.\r\n" );
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document.write( "Then\r\n" );
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document.write( " = 540 is effective speed against the wind, which is the difference u-v:\r\n" );
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document.write( "u - v = 540      (1)\r\n" );
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document.write( " = 1020 is effective speed with the wind, which is the sum u+v:\r\n" );
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document.write( "u + v = 1020     (2)\r\n" );
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document.write( "Add equations (1) and (2) to get\r\n" );
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document.write( "2u = 1560  ====>  u =  = 780 km/h  is the airplane speed at no wind.\r\n" );
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document.write( "Then from (1)  v = 1020 - 780 = 240 km/h  for the wind.\r\n" );
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document.write( "This result for the wind TELL you that the problem is very BADLY DESIGNED, because 240 km/h is more than an hurricane speed \r\n" );
document.write( "and any flights are prohibited under such conditions.\r\n" );
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document.write( "I don't like very much to work with badly designed problems.\r\n" );
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document.write( "My personal opinion is that their creators deserve a punishment.\r\n" );
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