SOLUTION: A truck travels 240km. If it had travelled an average 10km/h faster the trip would have been 2 hours shorter. What was the actual average speed in km/h of the truck?

Question 760238: A truck travels 240km. If it had travelled an average 10km/h faster the trip would have been 2 hours shorter. What was the actual average speed in km/h of the truck?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
A truck travels 240km. If it had travelled an average 10km/h faster the trip would have been 2 hours shorter. What was the actual average speed in km/h of the truck?
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d = r*t = 240 km
t = 240/r
t-2 = 240/(r+10)
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(240/r)-2 = 240/(r+10)
(240 - 2r)/r = 240/(r+10)
240r = (240 - 2r)*(r+10)
120r = (120 - r)*(r+10)

(r+40)*(r-30) = 0
r = 30 km/hr

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