Question

The length of a train is 50 metres and it passes a pole in 2 second bridge of length 550 m, if speed of train is reduced to three-fifth​

Answer 1

Answer:

A train moving with a uniform speed crosses a pole in 2 sec and a 250m long bridge in 7 seconds. What is the length of the train?

Let the length of the train be x meter.

Train crossed the pole is 2 sec. So distance covered in 2 sec. is x meter.

Hence, the speed of train = distance / time = x / 2 ——- (1)

In second case,

Total distance covered by train is = ( x + 250) meter

Time take = 7 second

So, speed of train = (x + 250 ) / 7 ——(2)

From (1) and (2)

x/2 = (x+250)/7

7x = 2x + 500

5x = 500

x = 100

Hence the length of train is 100m

Answer 2

Answer:

Distance covered by train the cross the bridge (from front of engine to back of last wagon )

d=250+50=300 m

Speed of train v=10 m/s

Thus time taken t=

v

d

⟹ t=

10

300

=30 sec