Question

A train 210 m long is traveling at a speed of 42 Km/hr. A man is running at a speed of 6 Km/hr in the same direction to the motion of the train. What would be the time taken by the train to cross the man (in seconds)?

• A. 41 sec
• B. 31 sec
• C. 11 sec
• D. 21 sec

Answer 1

The correct option is D

21 sec

Time taken = Distance travelled / Speed

Here, Distance = length of the train( man doesn't have distance, so it is neglected) = 210 m

Speed, here it is Relative speed, as they are moving in same direction, their relative speed = 42 Km/hr - 6 Km/hr = 36 Km/hr, but we have to convert it into m/s. So, $36\times \frac{5}{18}=10m/s$

So now, the time taken by the train to cross the man (in m/s)= $\frac{210m}{10m/s}=21sec$