Reasoning : Logical Reasoning & Analytical Ability

Q 303 / 325

UPSC CSE Prelims 2012

Examine the following statements:

  1. Either A and B are of the same age or A is older than B.
  2. Either C and D are of the same age or D is older than C.
  3. B is older than C.

Which one of the following conclusions can be drawn from the above statements?

EXPLANATION

Correct Option (d)

Statement 1 indicates that A is either older than or the same age as B (A ≥ B). Statement 3 explicitly states that B is older than C (B > C).

By combining these two relationships:

  • If A is the same age as B (A = B), then since B > C, it logically follows that A > C.
  • If A is older than B (A > B), then since B > C, it also logically follows that A > C.

In both possible interpretations of Statement 1, considering Statement 3, the conclusion that A is older than C is consistently valid.

Incorrect Options

  • Option (a) A is older than B: Statement 1 establishes A ≥ B. This implies that A could be the same age as B. Therefore, it cannot be definitively concluded that A is strictly older than B.

  • Option (b) B and D are of the same age: Statement 2 indicates D ≥ C (D is either older than or the same age as C). Statement 3 states B > C. While B is older than C, there is no information provided to establish a direct or conclusive age relationship between B and D, nor to ascertain that they are of the same age. For example, if D = C, then B would be older than D.

  • Option (c) D is older than C: Statement 2 establishes D ≥ C. This includes the possibility that D and C are of the same age. Therefore, it cannot be definitively concluded that D is strictly older than C.