The letters L, M, N, O, P, Q, R, S and T in their order are substituted by nine integers 1 to 9 but not in that order. 4 is assigned to P. The difference between P and T is 5. The difference between N and T is 3. What is the integer assigned to N ?
- (a) 7
- (b) 5
- (c) 4
- (d) 6 ✓ UPSC's answer
Why the answer is (d)
• P is assigned the integer 4.
• The difference between P and T is 5, so T is either 4 + 5 = 9 or 4 - 5 = -1.
• Since the integers are from 1 to 9, T must be 9.
• The difference between N and T is 3, so N is either 9 + 3 = 12 or 9 - 3 = 6.
• Since the integers are from 1 to 9, N must be 6.
• Therefore, the integer assigned to N is 6.
Why the other options are wrong
- (a) 7
- 7 is incorrect because the difference between 7 and T (9) is 2, not 3.
- (b) 5
- 5 is incorrect because the difference between 5 and T (9) is 4, not 3.
- (c) 4
- 4 is incorrect because 4 is already assigned to P, and the difference between 4 and T (9) is 5, not 3.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2014, held on 24 August 2014. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.