document.write( "Question 246310: A train normally travels 60 miles at a certain speed. One day, due to bad weather, the train's speed is reduced by 10 mph so that the journey takes 3 hours longer. Find the normal speed. \n" ); document.write( "
Algebra.Com's Answer #180014 by ankor@dixie-net.com(22740)\"\" \"About 
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A train normally travels 60 miles at a certain speed. One day, due to bad weather, the train's speed is reduced by 10 mph so that the journey takes 3 hours longer.
\n" ); document.write( " Find the normal speed.
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\n" ); document.write( "Let s = the normal speed
\n" ); document.write( "then
\n" ); document.write( "(s-10) = the slower speed
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\n" ); document.write( "Write a time equation, Time = dist/speed
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\n" ); document.write( "Normal time + 3 hr = Slower time
\n" ); document.write( "\"60%2Fs\" + 3 = \"60%2F%28%28s-10%29%29\"
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\n" ); document.write( "Multiply by s(s-10), results
\n" ); document.write( "60(s-10) + 3s(s-10) = 60s
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\n" ); document.write( "60s - 600 + 3s^2 - 30s - 60s = 0
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\n" ); document.write( "Combine as a quadratic equation
\n" ); document.write( "3s^2 - 30s - 600 = 0
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\n" ); document.write( "Simplify, divide by 3
\n" ); document.write( "s^2 - 10s - 200 = 0
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\n" ); document.write( "Factor
\n" ); document.write( "(s-20)(s+10) = 0
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\n" ); document.write( "Positive solution;
\n" ); document.write( "s = 20 mph is the normal speed
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\n" ); document.write( "Check solution, find the times of each trip
\n" ); document.write( "60/10 = 6 hr, slow time
\n" ); document.write( "60/20 = 3 hr, normal time
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\n" ); document.write( "diff = 3 hrs \n" ); document.write( "
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