IBPS SO Prelims Exam Model Paper 5

To find time taken by train to cross bridge let’s check each statement individually-
Statement I-
Length of bridge is 500 meters.
∴ to cross a bridge train travels distance that is sum of lengths of bridge and its own length.
But statement I fails to give information about length of train.
∴ Statement I alone is not sufficient to find time taken by train to cross bridge.
Statement II-
The length of train is 500 meters.
As given length of train = 500 meters
∴ to cross a bridge train travels distance that is sum of lengths of bridge and its own length.
But statement II fails to give information about length of bridge.
∴ Statement II alone is not sufficient to find time taken by train to cross bridge.
By combining information of both statements.
We know length of train = 500 meters.
& length of bridge = 500 meters.
∴ Total distance traveled by train while crossing bridge = length of train + length of tunnel
∴ Total distance traveled by train while crossing bridge = 500 + 500
∴ Total distance traveled by train while crossing bridge = 1000 meters = 1km
By using formula of distance, time and speed-
Time taken by train to cover 1 km =

distance

speed

=

1

120

hours
∴ Time taken by train to cross bridge is 0.5 minute.
∴ Both statements are necessary to find time taken by train to cross the bridge.