Question

a 350 m long train passes over a 250m long bridge at the speed of 54km/hr how long will it take to cross the bridge

Answer 1

Length of train = 350 m = 0.35 km
Length of bridge = 250m = 0.25 km
=>Total distance to be covered by the train = (0.35 + 0.25)km = 0.6 km
=>Time it will take to do so = distance/speed = 0.6/54 = 0.01 hr
                                               = 0.6 minutes = 36 seconds.

Hope it helps!!

Answer 2

Train's length=350m=0.35km.
Bridge's length=250m=0.25km.

Total distance to be covered by the train=0 35+0.25km=0.6km.

Time it will take to do so=distance/speed=0.6/54=0.01 hr.

=0.6
=minutes=36 seconds.

Hope it helps you dear