The speed of a train is 75 km/h, it crosses a tunnel in 75 seconds and overtakes a person walking at a speed of 5 km/h, in the same direction, in 27 seconds. The length (in meter) of the tunnel is:

600

Distance = Speed × Time

54 km/h  ×  \(\frac{5}{18}\) =   15 m/sec 

length of (Train + Tunnel) = 15 × 75 = 1125 m

length of (Train + Tunnel) =  1125 m

Relative speed of Train and man = (75 - 5) km/hr

Length of  Train = (75 - 5) × \(\frac{5}{18}\) × 27 = 525 m

 Length of Tunnel = 1125 - 525 = 600 m