# A train speed past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is ?

A train speed past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is ?

A. 50 m

B. 150 m

C. 200 m

D. None of these

**Answer : **B. 150 m

## Explanation :

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

Then, x / y = 15

=> y = x / 15

(x + 100) / 25 = x / 15

=> 15(x + 100) = 25x

=> 15x + 1500 = 25x

=> 1500 = 10x

=> x = 150 m.