document.write( "Question 1168485: Trains at each end of a 26 km long tunnel start at the same time. Find the speed (in km/hr) of the faster train if it travels 8.1 km/h faster than the other. They pass each other in the tunnel after 12.4 minutes.\r
\n" ); document.write( "\n" ); document.write( "Express your answer to three significant digits. Do not include units in your answer. \n" ); document.write( "
Algebra.Com's Answer #793070 by Boreal(15235)\"\" \"About 
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slower travels at x km/min (note units) *12.4 min or 12.4x km
\n" ); document.write( "faster travels at (x+0.135)km/min and the 0.135 is 8.1 km/h converted to min.and its distance is 12.4(x+0.135)
\n" ); document.write( "or 12.4x+1.674 km
\n" ); document.write( "Those two describe 26 km in distance since the time is already considered.
\n" ); document.write( "12.4x+12.4x+1.674 km=26 km
\n" ); document.write( "24.8 x= 24.326 km
\n" ); document.write( "x=0.9809 km/min (not rounded from calculator).
\n" ); document.write( "multiply by 60 for x=58.85 or 58.9 km/h and x+8.1 =67 km/h, the answer being 58.9, 67, without units.\r
\n" ); document.write( "\n" ); document.write( "Check using hours
\n" ); document.write( "The two are approaching each other at 2x+8.1 km/h. In 12.4 minutes they meet, or 0.206667 hours.\r
\n" ); document.write( "\n" ); document.write( "that is the time for the combined distance to be 26 km, so the combined speed is 26/0.2066667 or 125.80 km/h\r
\n" ); document.write( "\n" ); document.write( "x+x+8.1=125.8
\n" ); document.write( "2x=117.7
\n" ); document.write( "x=58.85 km/h as above.
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