The speed of a train is 156 km/h. It crosses a tunnel in 45 seconds and overtakes a person walking at a speed of 12 km/h in the same direction in 15 seconds. The length (in m) of the tunnel is?
Answer & explanation
Correct answer: option 1
Length of train = lt
Relative speed = 156 - 12 = 144 km/h
lt = 144 × \(\frac{5}{18}\) × 15 = 40 × 15 = 600 m
600 + LTunnel = 156 × \(\frac{5}{18}\) × 45 = 26 × 5 × 15 = 1950
LTunnel = 1950 - 600 = 1350 m