Correct Answer - Option 1 : 115.2 km/h
Given:
Length of train = 130 m
Length of bridge = 110 m
Time taken to cross to bridge = 7.5 seconds
Concept:
The length calculated to cross the bridge is the length of the train and the bridge added together.
Formula used:
Speed = Distance/Time
Conversion from m/s to km/h = Multiply with 18/5
Calculation:
The total distance travelled by the train = 130 m + 110 m
⇒ 240 m
Speed of the train while crossing the bridge = 240/7.5 m/s
⇒ 32 m/s
Speed of the train in km/h = {32 × (18/5)} km/h
⇒ 115.2 km/h
∴ The speed of the train is 115.2 km/h.