Correct Answer - Option 4 : 54 km/hr
Given :
Length of train = 400 m
length of tunnel = 200 m
time taken = 40 seconds
Formula used
speed = distance/time
1 m/s = 18/5 km/hr
Calculation
total distance = 400 + 200 = 600 m
speed = 600/40 = 15 m/s
Speed in km/hr = 15 × 18/5 = 54 km/hr
∴ The speed of the train is 54 km/hr.
