Train A crosses a stationary train B of length 700 m in 60 seconds. The train crosses another stationary train C of 800 m in 80 seconds. What is the speed of the train A(in m/s)?

Train A crosses a stationary train B of length 700 m in 60 seconds. The train crosses another stationary train C of 800 m in 80 seconds. What is the speed of the train A(in m/s)? Correct Answer 5

Given:

Train A crosses a stationary train B of length 700 m in 60 seconds. The train crosses another stationary train C of 800 m in 80 seconds.

Formula used:

Time Taken by a train of length l₁ to cross another train of length l₂ when the speed of the first train is v and the second train is stationary = (l₁ + l₂)/v

Calculation:

Let the length of train A be l and the speed be v.

⇒ l + 700 = 60v     ….(i)

⇒ l + 800 = 80v     ….(ii)

Comparing l in the above equations,

⇒ 60v – 700 = 80v – 800

⇒ 100 = 20v

⇒ v = 5 m/s

∴ required speed of the train A = 5 m/s.