1.  A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
A. 320 m
B. 350 m
C. 650 m
D. Data inadequate
E. None of these

Answer: Option B

Explanation:

Speed = ( 300 ( m/sec = 50 m/sec.
18 3

Let the length of the platform be x metres.

Then, ( x + 300 ( = 50
39 3

=> 3(x + 300) = 1950

=> x = 350 m.