document.write( "Question 811061: a car traveled 252 miles averaging a certain speed if the car would have drove six miles per hour faster the trip would have taken 1 hour less find the average speed? \n" ); document.write( "

Algebra.Com's Answer #488633 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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a car traveled 252 miles averaging a certain speed if the car would have drove six miles per hour faster the trip would have taken 1 hour less
\n" ); document.write( " find the average speed?
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\n" ); document.write( "Let s = the average speed
\n" ); document.write( "then
\n" ); document.write( "(s+6) = the faster speed
\n" ); document.write( ":
\n" ); document.write( "Write a time equation; time = dist/speed
\n" ); document.write( " $\"252%2Fs\"$ - $\"252%2F%28%28s%2B6%29%29\"$ = 1
\n" ); document.write( "multiply by s(s+6), resutlts
\n" ); document.write( "252(s+6) - 252s = s(s+6)
\n" ); document.write( "252s + 1512 - 252s = s^2 + 6s
\n" ); document.write( "Arrange as a quadratic equation on the right
\n" ); document.write( "0 = s^2 - 6s - 1512 = 0
\n" ); document.write( "This will factor to
\n" ); document.write( "(s+42)(s-36) = 0
\n" ); document.write( "the positive solution
\n" ); document.write( "s = 36 mph is the average speed
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check this by finding the time at each speed (fast speed = 42 mph)
\n" ); document.write( "252/36 = 7 hrs
\n" ); document.write( "252/42 = 6 hrs, one hr difference \n" ); document.write( "

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