Consider 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 of the following conclusions can be drawn from the above statements ?
- (a) A is older than B
- (b) B and D are of the same age
- (c) D is older than C
- (d) A is older than C ✓ UPSC's answer
Why the answer is (d)
• Statement 1 says A is either the same age as B or older than B, so A is at least as old as B.
• Statement 2 says D is either the same age as C or older than C, so D is at least as old as C, but it does not force D to be older than C.
• Statement 3 says B is older than C, so B > C.
• Combining A >= B and B > C gives A > C, because if A equals B, A is still older than C, and if A is older than B, A is even more older than C.
• Therefore, the only conclusion that must follow is that A is older than C, which is option (d).
Why the other options are wrong
- (a) A is older than B
- A may be the same age as B, so A being older than B is not certain.
- (b) B and D are of the same age
- B and D need not be the same age because only B > C and D >= C are given.
- (c) D is older than C
- D may be the same age as C, so D being older than C is not certain.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2016, held on 7 August 2016. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.