A train 100m long travelling at 40 m/s starts overtaking another train 200 m long travelling at 30m/s in the same direction. The time taken by the first train to pass the second train completely is :

Options

A. 30s
B. 40s
C. 50s
D. 60s

Answer

a

Explanation

Relative distance m Relative velocity = 10 m/s Time taken = 30 s