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**.