UPSC Prelims 2019·CSAT·Logical Reasoning·Clocks and Calendars

Which year has the same calendar as that of 2009 ?

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Last updated 23 May 2026, 3:31 pm IST
  1. A2018
  2. B2017
  3. C2016
  4. D2015Correct

Explanation

To determine if a calendar repeats, we count the number of odd days until the sum reaches a multiple of 7. An ordinary year has 1 odd day and a leap year has 2 odd days. Starting from 2009: 2009 is an ordinary year: 1 odd day 2010 is an ordinary year: 1 odd day 2011 is an ordinary year: 1 odd day 2012 is a leap year: 2 odd days 2013 is an ordinary year: 1 odd day 2014 is an ordinary year: 1 odd day Total odd days from 2009 to 2014 = 1 + 1 + 1 + 2 + 1 + 1 = 7 days. Since the total number of odd days becomes exactly 7 (which is divisible by 7) at the end of 2014, the next year, 2015, will have the same calendar as 2009. Both 2009 and 2015 are ordinary years, so the calendars match perfectly. Therefore, the correct option is D.
Logical Reasoning: Which year has the same calendar as that of 2009 ?

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