document.write( "Question 1042121: By increasing the average speed of motorista by 10 miles per hour he would have save 36 minutes in traveling a distance of 120 miles. Find the average speed. \n" ); document.write( "
Algebra.Com's Answer #657058 by stanbon(75887)\"\" \"About 
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By increasing the average speed of motorists by 10 miles per hour he would have saved 36 minutes in traveling a distance of 120 miles. Find the average speed.
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\n" ); document.write( "Original DATA:
\n" ); document.write( "distance = 120 miles ; rate = r mph ; time = 120/r hrs
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\n" ); document.write( "Faster travel DATA:
\n" ); document.write( "dist = 120 ; rate = r + 10 mph ; time = 120/(r+10) hrs
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\n" ); document.write( "Equation:
\n" ); document.write( "time - time = (36/60) hrs
\n" ); document.write( "120/r - 120/(r+10) = 36/60
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\n" ); document.write( "60(r+10)*120 - 60r*120 = 36r(r+10)
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\n" ); document.write( "60*10*120 = 36r^2 + 360r
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\n" ); document.write( "10*10*20 = r^2 + 10r
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\n" ); document.write( "r^2 + 10r - 2000 = 0
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\n" ); document.write( "r = 44.6 mph
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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