SOLUTION: For the first hour of a four hour trip, the average speed of a train was 40 km/h. If the average speed for the whole trip was 70 km/h, what was the average speed for the last th

Question 690811: For the first hour of a four hour trip, the average speed of a train was 40 km/h. If the average
speed for the whole trip was 70 km/h, what was the average speed for the last three hours of
the trip?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
average speed is distance/time
Let = distance traveled for the last 3 hrs of the trip
Let = the time in hrs for the whole trip
The distance for the 1st hour is
km
The distance for the whole trip is

The average speed for the whole trip was 70 km/h
The time for the whole trip was

The average speed for the last 3 hrs is 80 km/hr

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