Question

A train 300m long is travelling at a speed of 120 km/h how long Will it take to cross a bridge 200m long?

Answer 1

the train crosses the bridge when the last coach crosses the bridge so let's assume that trains engine is at the edge of bridge

distance of last coach from starting of bridge = 300 m

to cross the bridge , the last coach has to travel 500 (300+200) from initial position

time required = (500/1000)/120 = 1/240 hr

= 1/240*60*60 = 15 seconds