A train runs for 3 h at the speed of 40 km/h and then for 4 1/ 2 h at the speed of 60 km/h. Thus, it covers 3/5th part of the whole distance. It wants to cover the remaining distance in 4 h, find the average speed of the train for remaining distance?
Correct Answer: 65 km/h
Explanation:
Let total distance = D
Now, according to the question,
40 x 3 + 60 x 4.5 = 3D/5
⇒ 120 + 270 = 3D/5
∴ D = 390 x 5/3 = 650 km ∴ Remaining distance = [650 - (3/5) x 650]
= 650 - 390 = 260 km Required average speed = 260/4 = 65 km/h
