1. 

What is the speed of the train?

I. The train crosses a signal pole in 18 seconds.

II. The train crosses a platform of equal length in 36 seconds.

III. Length of the train is 330 metres.
A. I and II only
B. II and III only
C. I and III only
D. III and either I or II only
E. Any two of the three

Answer: Option D

Explanation:

Let the speed of the train be x metres/sec.

Time taken to cross a signal pole :

= Length of the train
Speed of the train

Time taken to cross a platform

= (Length of the train + Length of the Platform)
Speed of the train

Length of train = 330 m.

I and III give,

18 = 330     x = 330 m/sec = 55 m/sec.
x 18 3

II and III give,

36 = 2 x 330     x = 660 m/sec = 55 m/sec.
x 36 3

Correct answer is (D).