document.write( "Question 919187: Bianca travelled 1200km.if her average speed had been 5 more km per hour,she could have made the trip in 12 hours less time.find bianca s average speed \n" ); document.write( "

Algebra.Com's Answer #557525 by stanbon(75887) $\"\"$ $\"About$

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Bianca travelled 1200km.if her average speed had been 5 more km per hour,she could have made the trip in 12 hours less time.find bianca s average speed
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\n" ); document.write( "Original DATA:
\n" ); document.write( "dist = 1200 km ; rate = x mph ; time = 1200/x hrs
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\n" ); document.write( "Adjusted DATA:
\n" ); document.write( "dist = 1200 km ; rate = x+5 mph ; time = 1200/(x+5) hrs
\n" ); document.write( "-------
\n" ); document.write( "Equation:
\n" ); document.write( "orig time - adj time = 12 hrs
\n" ); document.write( "1200/x - 1200/(x+5) = 12 hrs
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\n" ); document.write( "1200x + 1200*5 - 1200x = 12x(x+5)
\n" ); document.write( "----
\n" ); document.write( "60000 = 12x^2 + 60x
\n" ); document.write( "x^2 + 5x - 5000 = 0
\n" ); document.write( "----
\n" ); document.write( "(x-68.25)(x+73.25) = 0
\n" ); document.write( "Positive solution:
\n" ); document.write( "x = 68.25 km/hr
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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