SOLUTION: By increasing the average speed of motorista by 10 miles per hour he would have save 36 minutes in traveling a distance of 120 miles. Find the average speed.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: By increasing the average speed of motorista by 10 miles per hour he would have save 36 minutes in traveling a distance of 120 miles. Find the average speed.      Log On


   

Question 1042121: By increasing the average speed of motorista by 10 miles per hour he would have save 36 minutes in traveling a distance of 120 miles. Find the average speed.
Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
By increasing the average speed of motorists by 10 miles per hour he would have saved 36 minutes in traveling a distance of 120 miles. Find the average speed.
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Original DATA:
distance = 120 miles ; rate = r mph ; time = 120/r hrs
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Faster travel DATA:
dist = 120 ; rate = r + 10 mph ; time = 120/(r+10) hrs
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Equation:
time - time = (36/60) hrs
120/r - 120/(r+10) = 36/60
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60(r+10)*120 - 60r*120 = 36r(r+10)
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60*10*120 = 36r^2 + 360r
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10*10*20 = r^2 + 10r
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r^2 + 10r - 2000 = 0
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r = 44.6 mph
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Cheers,
Stan H.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

By increasing the average speed of motorista by 10 miles per hour he would have save 36 minutes in traveling a distance of 120 miles. Find the average speed.
Average speed: highlight_green%28matrix%281%2C2%2C+40%2C+mph%29%29