If in a particular year 12th January is a Sunday, then which one of the following is correct?
- (a) 15th July is a Sunday if the year is a leap year.
- (b) 15th July is a Sunday if the year is not a leap year.
- (c) 12th July is a Sunday if the year is a leap year. ✓ UPSC's answer
- (d) 12th July is not a Sunday if the year is a leap year.
Why the answer is (c)
• 12 January is Sunday; count the days from 12 January to 12 July.
• In a leap year, the interval is 31 + 29 + 31 + 30 + 31 + 30 = 182 days.
• 182 days is exactly 26 weeks, so 12 July is also Sunday in a leap year.
• In a non-leap year, the interval is 31 + 28 + 31 + 30 + 31 + 30 = 181 days, i.e. 25 weeks + 6 days, so 12 July is Saturday.
• 15 July is 3 days after 12 July, making it Wednesday in a leap year and Tuesday in a non-leap year.
• Therefore option (c) is correct.
Why the other options are wrong
- (a) 15th July is a Sunday if the year is a leap year.
- 15th July is Wednesday in a leap year, not Sunday.
- (b) 15th July is a Sunday if the year is not a leap year.
- 15th July is Tuesday in a non-leap year, not Sunday.
- (d) 12th July is not a Sunday if the year is a leap year.
- 12th July is Sunday in a leap year, so it is not correct to say it is not a Sunday.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2020, held on 4 October 2020. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.