A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?

by
Question: A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?
[A].

69.5 km/hr

[B].

70 km/hr

[C].

79 km/hr

[D].

79.2 km/hr

Answer: Option D

Explanation:

Let the length of the train be x metres and its speed by y m/sec.

Then, x = 8         x = 8y
y
Now, x + 264 = y
20

8y + 264 = 20y

y = 22.

Speed = 22 m/sec = 22 x 18 km/hr = 79.2 km/hr.
5