document.write( "Question 1069683: X an Y are two stations 500 km apart. A train starts form X and moves towards Y at 20 km/hr. Another rain starts from Y at the same time and moves towards X at 30 km/hr. How far from X will they cross each other: \n" ); document.write( "

Algebra.Com's Answer #684838 by ikleyn(52802) $\"\"$ $\"About$

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document.write( "Time they travel before they cross each other is   = 10 hours.\r\n" );
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document.write( "During 10 hours the first train covers  10*20 = 200 km.\r\n" );
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document.write( "Answer.  200 km.\r\n" );
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\n" ); document.write( "\n" ); document.write( "The tutor \"MathTherapy\" wrote his own solution.
\n" ); document.write( "Probably, he tried to prove that I made a mistake in my solution.\r
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\n" ); document.write( "\n" ); document.write( "But instead, he made a mistake in his own solution.\r
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\n" ); document.write( "\n" ); document.write( "Below I re-wrote his solution with my correction. It gives the same result/answer as my original solution.
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With D being the distance from X where they cross, we get the following TIME equation: \r\n" );
document.write( "30D = 20(500 - D) ------- Cross-multiplying\r\n" );
document.write( "30D = 10,000 - 20D\r\n" );
document.write( "30D + 20D = 10,000\r\n" );
document.write( "50D = 10,000\r\n" );
document.write( "D, or distance form X where they cross = \r\n" );
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