Question

a train moving with constant speed crosses a pole in 20 s and a tunnel of lenght 500m in 70s. The speed of train is
a)18 km/hr
b)36 km/hr
c)54 km/hr
d)72 km/hr
the answer is 36km/hr explain ur answer

Answer 1

Answer:

The speed of the train 36 km/hr

Explanation:

Let the length of the train is x

and speed of the train is y m/s

According to the problem the train crossed a pole in 20 s

therefore

x/y = 20

x = 20y...(i)

Then the train crossed a 500 m long tunnel in 70 sec

therefore

x+500/y= 70

x = 70y- 500 ...(ii)

from (i) and (ii)

70y- 500 = 20 y

50y = 500

y= 10 m/s

therefore the speed of the train is 10 m/s or 36 km/hr