Which year has the same calendar as that of 2009?
Answer & explanation
Answer: (d) 2015
A year repeats 2009's calendar when the odd days carried forward total a multiple of 7 and it is also a non-leap year. From 2009 the odd days add up to 1 + 1 + 1 + 2 + 1 + 1 = 7 by the start of 2015, and 2015 is not a leap year.
- Odd days carried by each year: 2009 → 1, 2010 → 1, 2011 → 1, 2012 (leap) → 2, 2013 → 1, 2014 → 1.
- Total to the start of 2015 = 7, a full week, so 1 January 2015 falls on the same weekday as 1 January 2009.
- 2015, like 2009, is not a leap year, so the whole calendar matches.
- Check: 2016 would carry 8 odd days (≡ 1) and is a leap year, so it cannot match.
Remember · Same calendar = total odd days ≡ 0 (mod 7) and the same leap-year status.
Question and answer: UPSC's official GS Paper II (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·