Answered

A train travels a total distance of 600km in eight hours.It travels the first 120 km at a speed of 60km/h, travels the next 180km in two hours and then completes the trip at an unknown speed. What was the average speed of the train for the last leg of the trip? What is the average speed of the train for the entire trip?



Answer :

the first two hours were 60 km/h, 120 km travelled 
the next two were 90 km/h, 180 km travelled
a total of 300 km and 4 hours are remaining, so the speed for the last leg of the trip would be 300 / 4, or 75 km/h.
the average speed of the train for the entire trip would be distance / time, 600 / 8, which would be 75 km/h