A train has 20 carriages, each of which is 15m long. The train takes 30 seconds to cross a man standing beside the rail

[Mikrislac]

A train has 20 carriages, each of which is 15m long. The train takes 30 seconds to cross a man standing beside the rail tracks. If 4 carriages are removed from the train, then how much time will the train take to cross the man? Assume that the man has negligible dimensions.

A. 15 seconds
B. 20 seconds
C. 24 seconds
D. 25 seconds
E. 27 seconds

[Mikrislac]

Since the speed of the train is constant in the two cases (assumed), the distance travelled by the train will be directly proportional to the time it takes to cross a point (such as a standing man of negligible dimensions).

We are given that 20 carriages (of length 20*15m) cross the man in 30 seconds. So, 1 carriage will take 30 seconds/20 carriages = 1.5 second per carriage to cross the man. Therefore, 16 carriages (4 carriages have been removed) will take 16*1.5 seconds = 24 seconds.

Answer: C