document.write( "Question 1149914: The first train started eastwards at 40mph. One hour later, the second train starts southwards at 60mph. How fast in mph, are the two trains separating 2 hours after the start of the 2nd train? \n" ); document.write( "

Algebra.Com's Answer #771407 by ikleyn(52921) $\"\"$ $\"About$

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document.write( "Let \"t\" be the time after second train started.\r\n" );
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document.write( "The we have for distances from the starting point\r\n" );
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document.write( "    First train :  x(t) = 40 + 40*t\r\n" );
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document.write( "    Second train : y(t) = 60*t\r\n" );
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document.write( "The distance between the trains is  z(t) =  = \r\n" );
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document.write( "The rate of separating, which the problem is asking about, is\r\n" );
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document.write( "     =  \r\n" );
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document.write( "Now substitute  t= 2 hours into the last formula and calculate\r\n" );
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document.write( "     =  =  = 70.711 km/h.    ANSWER\r\n" );
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