document.write( "Question 434379: A car travels 910 miles at a certain speed. If the speed had been 5mph faster the trip would have been made 1hour less time. Find the speed? \n" ); document.write( "
Algebra.Com's Answer #300994 by ankor@dixie-net.com(22740)\"\" \"About 
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A car travels 910 miles at a certain speed.
\n" ); document.write( "If the speed had been 5mph faster the trip would have been made 1hour less time.
\n" ); document.write( " Find the speed?
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\n" ); document.write( "Let s = actual speed
\n" ); document.write( "then
\n" ); document.write( "(s+5) = hypothetical 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 = 1 hr
\n" ); document.write( "\"910%2Fs\" - \"910%2F%28%28s%2B5%29%29\" = 1
\n" ); document.write( "Multiply equation by s(s+5), results:
\n" ); document.write( "910(s+5) - 910s = s(s+5)
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\n" ); document.write( "910s + 4550 - 910s = s^2 + 5s
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\n" ); document.write( "Combine to form a quadratic equation
\n" ); document.write( "0 = s^2 + 5s - 4550
\n" ); document.write( "You can solve this with the quadratic equation, but it will factor to:
\n" ); document.write( "(s + 70)(s - 65) = 0
\n" ); document.write( "The positive solution
\n" ); document.write( "s = 65 mph is the actual speed
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\n" ); document.write( "See if that's true
\n" ); document.write( "910/65 - 910/70
\n" ); document.write( "14 - 13 = 1 hr\r
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