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UPSC Prelims 2025CSATGeneral Mental AbilitySeries Completion - Word/Letter Series

Q38. 38. What comes at X and Y respectively in the following sequence? January, January, December, October, X, March, October, Y, September

A. July, May
B. July, April✓ Correct
C. June, May
D. June, April

Detailed Solution

✓ Correct Answer: Option B

Let's assign numerical values to the months (January=1, February=2, ..., December=12). The sequence is: 1, 1, 12, 10, X, 3, 10, Y, 9. Observe the pattern of differences, considering a 12-month cycle: * January (1) - 0 = January (1) * January (1) - 1 = December (12) (1 - 1 = 0, which is month 12 in a cycle) * December (12) - 2 = October (10) * October (10) - 3 = July (7).

So, X = July. * July (7) - 4 = March (3) * March (3) - 5 = October (10) (3 - 5 = -2, which is month 10 in a cycle, i.e., -2 + 12 = 10) * October (10) - 6 = April (4). So, Y = April.

* April (4) - 7 = September (9) (4 - 7 = -3, which is month 9 in a cycle, i.e., -3 + 12 = 9) The pattern involves subtracting consecutive integers (0, 1, 2, 3, 4, 5, 6, 7...) from the numerical value of the month, wrapping around the 12-month cycle. Thus, X is July and Y is April.

This is a logical reasoning question requiring pattern identification, common in CSAT.

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