Question

Beth is taking the train to see her boyfriend on Valentine's day! The train is 100 meters long and it takes 30 seconds to cross a 400m bridge. What speed is the train going at?

Answer 1

Speed of train is 16.666 metres/second or 60 KMPH

Total distance the train has to cover to cross the bridge = length of bridge + length of train. 

Explanation: The train has to cover 400 metres of the bridge, and its own length of 100 metres to fully cross the bridge.

Total distance = 500 metres

Time taken = 30 seconds

Speed = distance / time

500 / 30 = 16.666 metres/second or 60 KMPH

Answer 2

Solution:-

given by;-

》time = 30s

》length of train = 100m

》length of bridge = 400m

》total distance = 100+400 = 500m

》train speed = 500/30 = 50/3m/s

》train speed in hour = 60km/h
$\frac{50 \times 60 \times 60}{3 \times 1000} \\ 60 \frac{km}{h}$

i hope its is help