document.write( "Question 724036: tera traveled 120 miles at a certain speed. tara then drove another 100 miles at a speed that was 10 mph slower. If the total time of taras trip was 4 hours, what was her speed at each part of the trip \n" ); document.write( "

Algebra.Com's Answer #443553 by stanbon(75887) $\"\"$ $\"About$

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tera traveled 120 miles at a certain speed. tara then drove another 100 miles at a speed that was 10 mph slower. If the total time of taras trip was 4 hours, what was her speed at each part of the trip
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\n" ); document.write( "1st leg DATA:
\n" ); document.write( "distance = 120 miles ; speed = x mph ; time = 120/x hrs
\n" ); document.write( "----
\n" ); document.write( "2nd leg DATA:
\n" ); document.write( "distance = 100 miles ; speed = x-10 mph ; time = 100/(x-10) hrs
\n" ); document.write( "----
\n" ); document.write( "Equation:
\n" ); document.write( "120/x + 100/(x-10) = 4 hrs
\n" ); document.write( "-----
\n" ); document.write( "Modify:
\n" ); document.write( "30/x + 25/(x-10) = 1
\n" ); document.write( "30(x-10) + 25x = x^2-10x
\n" ); document.write( "---
\n" ); document.write( "x^2 -10x - 55x + 300 = 0
\n" ); document.write( "----
\n" ); document.write( "x^2 - 65x +300 = 0
\n" ); document.write( "----
\n" ); document.write( "(x-60)(x-5) = 0
\n" ); document.write( "Positive useful solution:
\n" ); document.write( "x = 60 mph
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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