SOLUTION: If you drive 2 h at 80 km/h, how fast must you drive during the next hour in order to have an average speed of 75 km/h?

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Question 29329: If you drive 2 h at 80 km/h, how fast must you drive during the next hour in order to have an average speed of 75 km/h?
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
average speed = total distance/time taken

First, the initial part:
80 = distance/2
--> distance = 160km.

So, for average speed of 75, we have travelled 160+x, where x is the distance we are asked for. Total time is 3 hours. So,

(160+x)/3 = 75
160+x = 225
x = 65km.

jon.