If 25 th May in a certain year is a Sunday, then which day of the week will be 25 th December in that year ?

The correct answer is C, Thursday.

Count the days from 25 May to 25 December. May 25 to June 25 is 31 days, June 25 to July 25 is 30, July 25 to August 25 is 31, August 25 to September 25 is 31, September 25 to October 25 is 30, October 25 to November 25 is 31, and November 25 to December 25 is 30. The total is 214 days. February falls outside this stretch, so leap year status does not matter.

214 divided by 7 leaves a remainder of 4. Moving 4 days forward from Sunday gives Thursday.

• Option A (Saturday): would need a remainder of 6, which is not what we get.
• Option B (Friday): would need a remainder of 5.
• Option D (Sunday): would need a remainder of 0, meaning the gap is a multiple of 7 days. 214 is not.

Core concept: this is the odd-days method. A shift of a fixed date across months is the sum of month lengths taken modulo 7. The same logic drives calendar and day-of-week questions in reasoning papers, and it is a quick, reliable tool to keep ready.

Trap: aspirants often mis-remember month lengths, such as giving May 30 days or September 31, or add an extra day for February even when it is not in the interval. Write out the month-by-month count rather than estimating.