Ch-12 :- Data – Sufficiency : Introduction & formula


Directions : The questions below consist of a question followed by two statements labelled as I and II. You have to decide if these statements are sufficient to conclusively answer the question. Give your answer as :

(a) if statement I alone is sufficient to answer the question;

(b) if statement II alone is sufficient to answer the question;

(c) if statement I and II together are needed to answer the question;

(d) if statement I or II alone are sufficient to answer the question;

(e) if statement I and II together also are not sufficient to answer the question.

1. Who is older – Ritu or Situ 7

I. Situ was born in the year 1980 and is 5 years younger than Ritu’s brother.

II. Ritu is twice as old as her brother.

Sol.On the basis of statement I, we can be certain that Situ is younger than Ritu’s brother but we can’t find the age relationship between Ritu and Situ. Therefore statement I, alone is not sufficient to answer the question. Statement II alone is not sufficient to answer the question as from this also we can’t establish age relationship between Situ and Ritu. From statement I, we find that Ritu’s brother is older than Situ and from statement II, we find that Ritu is older than her brother. from both the informations we conclude that Ritu is older than Situ. Hence, option (c) is the correct answer.

2. Six persons A, B, C, D , E and F are sitting in a row. A and F are sitting at two extreme ends of the row. B is to the immediate right of A and D is 2nd left of F. What is the position of E with respect to A?

I. E is to the right of A.

II. E is to the left of C.

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3. What is the sum of first two even natural numbers out of a group of five even natural numbers ?

I. The second number is double of the first number.

II. All the five numbers are consecutive even numbers.

Sol. From the statement I and II, we find that both the statements are not sufficient to answer the questions, as the series may start with any even natural number. Hence, option (e) is the correct answer.