Question

A person, sitting inside a train of length 80 m and travelling at speed of 54 kmph observes another train which is travelling at a speed of 90 kmph. Find the length of the other train, if the time duration to cross each other is 15 seconds. [ n.B. Both the trains are moving in the same direction]

Answer 1

Answer:

Explanation:

Speed of first train = 54 km/h = 54 x 5/18 = 15 m/s

Speed of 2nd train = 90 km/h = 90 x 5/18 = 25 m/s

Time duration = 15 sec.

Total length of the trains = Total distance = 80 + X ( X = length of the other train)

Distance = Speed x time

80 + X = Relative speed in same direction x time = (25 - 15) x 15

= 10 x 15 = 150

80 + X = 150

X = 150 - 80 = 70 m Ans.