Algebra.Com's Answer #853242 by ikleyn(53419)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
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document.write( "Flying from Tokyo to London is approximately 6175 miles.
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document.write( "On the way to London from Tokyo(against the wind) the flight took 13 hours.
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document.write( "the return flight (with the wind) took 9.88 hours.
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document.write( "Find the speed of the plane in still air and the speed of the wind current.
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document.write( " @mananth solved the problem making tons of unnecessary calculations.\r
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document.write( " Therefore, his solution can scary a reader and is a bad way to teach.\r
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document.write( " I will show below a standard solution approach to make minimum calculations.\r
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document.write( "The flight against the wind took 13 hours.\r\n" );
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document.write( "The effective rate was  = 475 miles per hour.\r\n" );
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document.write( "It gives you first equation \r\n" );
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document.write( " u - v = 475 mph (1),\r\n" );
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document.write( "since the effective rate against the wind is the difference of the airspeed u and the rate of the wind v.\r\n" );
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document.write( "The flight with the wind took 9.88 hours.\r\n" );
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document.write( "The effective rate was  = 625 miles per hour.\r\n" );
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document.write( "It gives you second equation \r\n" );
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document.write( " u + v = 625 mph (2),\r\n" );
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document.write( "since the effective rate with the wind is the sum of the airspeed u and the rate of the wind v.\r\n" );
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document.write( "Now you have a system of two equations for u and v.\r\n" );
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document.write( "To find u, add equations (1) and (2). The terms with 'v' cancel each other, and you will get\r\n" );
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document.write( " 2u = 475 + 625 = 1100, u = 1100/2 = 550.\r\n" );
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document.write( "Now from equation (2) v = 625 - 550 = 75.\r\n" );
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document.write( "Thus the problem is solved, and the ANSWER is\r\n" );
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document.write( " airspeed is 550 mph (the rate in still air, or relative the air), and\r\n" );
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document.write( " the rate of the wind is 75 mph.\r\n" );
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document.write( "Solved, making the minimum calculations - making only those calculations that are really needed.\r
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