1. 

Two cars pass each other in opposite direction. How long would they take to be 500 km apart ?

I. The sum of their speeds is 135 km / hr.

II. The difference of their speeds is 25 km / hr.

A. I alone sufficient while II alone not sufficient to answer
B. II alone sufficient while I alone not sufficient to answer
C. Either I or II alone sufficient to answer
D. Both I and II are not sufficient to answer
E. Both I and II are necessary to answer

Answer: Option A

Explanation:

I gives, relative speed = 135 km/hr.

Time taken = 500 hrs.
135

II does not give the relative speed.

I alone gives the answer and II is irrelevant.

Correct answer is (A).