1.  What is Ravi's present age? 

I. The present age of Ravi is half of that of his father. 

II. After 5 years, the ratio of Ravi's age to that of his father's age will be 6 : 11. 

III. Ravi is 5 years younger than his brother.
A. I and II only
B. II and III only
C. I and III only
D. All I, II and III
E. Even with all the three statements answer cannot be determined.

Answer: Option A

Explanation:

I. Let Ravi's present age be x years.

Then, his father's present age = 2x years.

 II. After 5 years, Ravi's age = 6
Father's age 11

III. Ravi is younger than his brother.

From I and II, we get x + 5 = 6 .   
2x + 5 11

This gives x, the answer.

Thus, I and II together give the answer. Clearly, III is redundant.

Correct answer is (A).