document.write( "Question 149484: A boy rides a bike 8 miles. The trip would have taken 20 minutes less if he had ridden 2 miles per hour faster. find his actual speed. \n" ); document.write( "
Algebra.Com's Answer #109674 by stanbon(75887)\"\" \"About 
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A boy rides a bike 8 miles. The trip would have taken 20 minutes less if he had ridden 2 miles per hour faster. find his actual speed.
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\n" ); document.write( "Original DATA:
\n" ); document.write( "distance = 8 miles ; rate = x mph ; time = d/r = 8/x hrs
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\n" ); document.write( "Modified DATA:
\n" ); document.write( "distance = 8 miles ; rate = (x+2) mph ; time = d/r = 8/(x+2)
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\n" ); document.write( "EQUATION:
\n" ); document.write( "old time - new time = 20/60 = 1/3 hr
\n" ); document.write( "8/x + 8/(x+2) = 1/3
\n" ); document.write( "Multiply thru by 3x(x+2)
\n" ); document.write( "24(x+2) + 24x = x(x+2)
\n" ); document.write( "48x + 48 = x^2 + 2x
\n" ); document.write( "x^2 - 46x - 48 = 0
\n" ); document.write( "-------
\n" ); document.write( "x = [46 +- sqrt(46^2 -4*1*-48)]/2
\n" ); document.write( "Positive solution:
\n" ); document.write( "x = [46 + sqrt(2300)]/2
\n" ); document.write( "x = 47.02.. mph (actual speed)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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