document.write( "Question 599365: By driving 8 mph faster than Bob, John can make a 230 mile trip in one half hour less. How fast does Bob drive on the trip? Round your answer to the nearest mile per hour \n" ); document.write( "
Algebra.Com's Answer #378937 by ankor@dixie-net.com(22740)\"\" \"About 
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By driving 8 mph faster than Bob, John can make a 230 mile trip in one half hour less.
\n" ); document.write( " How fast does Bob drive on the trip? Round your answer to the nearest mile per hour
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\n" ); document.write( "Let s = Actual speed
\n" ); document.write( "then
\n" ); document.write( "(s+8) = faster speed
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\n" ); document.write( "Write a time equation; time = dist/speed
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\n" ); document.write( "Actual time - faster time = .5 hrs
\n" ); document.write( "\"230%2Fs\" - \"230%2F%28%28s%2B8%29%29\" = .5
\n" ); document.write( ":
\n" ); document.write( "multiply by s(s+8), results:
\n" ); document.write( "230(s+8) - 230s = .5s(s+8)
\n" ); document.write( "230s + 1840 - 230s = .5s^2 + 4s
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\n" ); document.write( "Arrange as a quadratic equation
\n" ); document.write( ".5s^2 + 4s - 1840 = 0
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\n" ); document.write( "Make the coefficient of s 1, mult by 2
\n" ); document.write( "s^2 + 8s - 3680 = 0
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\n" ); document.write( "solve for s using the quadratic formula; a=1; b=8; c=-3680
\n" ); document.write( "I got a positive solution 56.8 mph \n" ); document.write( "
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