Question

A 120 m long train is moving in a direction with speed 20 m/s. A train B moving with 30 m/s in the opposite direction and 130 m long crosses the first train in a time

• A. $6s$
• B. 36 s
• C. 38 s
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

Total distance $= 130 + 120 = 250\mspace{6mu} m$

Relative velocity $= 30 - ( - 20) = 50\mspace{6mu} m/s$

Hence $t = 250/50 = 5s$