document.write( "Question 356937: Engine pulls train 140 miles, 2nd engine is 5 mph faster than first, takes over and pull the train 200 miles, total time required for 6 hrs. \r
\n" ); document.write( "\n" ); document.write( "find the average rate of each engine. \r
\n" ); document.write( "\n" ); document.write( "totally stuck on the setup of the problem..
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Algebra.Com's Answer #254881 by ankor@dixie-net.com(22740)\"\" \"About 
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Engine pulls train 140 miles,
\n" ); document.write( " 2nd engine is 5 mph faster than first, takes over and pull the train 200 miles,
\n" ); document.write( " total time required for 6 hrs.
\n" ); document.write( "find the average rate of each engine.
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\n" ); document.write( "Let s = speed of the slower engine
\n" ); document.write( "then
\n" ); document.write( "(s+5) = speed of the faster
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\n" ); document.write( "Write a time equation, Time = dist/speed
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\n" ); document.write( "Slow engine time + fast engine time = 6 hrs
\n" ); document.write( "\"140%2Fs\" + \"200%2F%28%28s%2B5%29%29\" = 6
\n" ); document.write( "multiply by s(s+5), results
\n" ); document.write( "140(s+5) + 200s = 6s(s+5)
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\n" ); document.write( "140s + 700 + 200s = 6s^2 + 30s
\n" ); document.write( "Arrange as a quadratic on the right
\n" ); document.write( "0 = 6s^2 + 30s - 140s - 200s - 700
\n" ); document.write( "6s^2 - 310s - 700 = 0
\n" ); document.write( "Simplify, divide by 2
\n" ); document.write( "3s^2 - 155s - 350 = 0
\n" ); document.write( "Use the quadratic formula to find the positive solution
\n" ); document.write( "\"x+=+%28-%28-155%29+%2B-+sqrt%28-155%5E2-4%2A3%2A-350+%29%29%2F%282%2A3%29+\"
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