What comes at X and Y respectively in the following sequence?
January, January, December, October, X, March, October, Y, September
Answer & explanation
Answer: (b) July, April
Counting forward, the gap between successive months shrinks by one each time: 12, 11, 10, 9, 8, 7, 6, 5 months. Nine months after October is July, and six months after October is April.
- Write the months as numbers: 1, 1, 12, 10, X, 3, 10, Y, 9.
- Count forward from each month to the next: January → January is 12 months, January → December is 11, December → October is 10.
- The gap falls by one each time: October + 9 months = July (X); July + 8 = March; March + 7 = October.
- October + 6 months = April (Y); April + 5 = September, which matches the last term.
- So X = July and Y = April.
Remember · For month or weekday series, convert to numbers and study forward gaps, wrapping around after 12 (or 7).
Question and answer: UPSC's official GS Paper II (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·