A train travels the distance between A and B at a speed of 60 km/h, while in the opposite direction it comes back at 90 km/h . Another train travels the same distance at the average speed of the first train . The time taken by the second train to travel 432 kms is :
Answer & explanation
Correct answer: option 1
Let the distance = 180 km [LCM of 60 and 90]
Average speed = \(\frac{Total\; Distance}{Total \;time}\) = \(\frac{2 \;×\; 180}{3 \;+\; 2}\) = 72 km/h
Time taken by second trrain = \(\frac{Distance}{Speed}\) = \(\frac{432}{72}\) = 6 h