Which day is 10th October, 2027?
Answer & explanation
Answer: (a) Sunday
Counting odd days gives 4 for the years 2001–2026 and 3 for 2027 up to 10 October — 7 in all, i.e. none left over, so the day is Sunday. A quicker route: this very paper was held on Sunday, 10 October 2021, and six years with one leap day add exactly 7 days.
- Odd days up to the end of 2000: 0 (every 400 years has 0 odd days).
- 2001–2026: 26 years with 6 leap years (2004, 2008, 2012, 2016, 2020, 2024), so 26 + 6 = 32 odd days; 32 = 4 × 7 + 4, leaving 4.
- 2027 up to 10 October: Jan 3, Feb 0, Mar 3, Apr 2, May 3, Jun 2, Jul 3, Aug 3, Sep 2, Oct 3 — total 24, leaving 3.
- Total = 4 + 3 = 7 odd days, i.e. 0, so 10 October 2027 is a Sunday.
- Check: 10 October 2021 (the date of this paper) was a Sunday; 2022–2027 add 6 + 1 (for 29 February 2024) = 7 days — Sunday again.
Remember · Anchor on a date you know: each ordinary year moves the weekday on by 1 and each leap year by 2.
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·