1. Introduction
Calendar problems deal with finding:
- Day of the week
- Odd days
- Leap years
- Dates and intervals
These questions are common in Reasoning & Quant sections.
2. Odd Days
Odd days are the extra days left after complete weeks.
Number of days → Odd days
- 1 year = 365 days = 1 odd day
- Leap year = 366 days = 2 odd days
- 100 years = 5 odd days
- 200 years = 3 odd days
- 300 years = 1 odd day
- 400 years = 0 odd days
3. Leap Year
A year is a leap year if:
- Divisible by 4, but not by 100,
- OR divisible by 400
Examples:
- 2020 ✔
- 1900 ✘
- 2000 ✔
4. Days in Months
| Month | Days |
|---|---|
| Jan | 31 |
| Feb | 28 / 29 |
| Mar | 31 |
| Apr | 30 |
| May | 31 |
| Jun | 30 |
| Jul | 31 |
| Aug | 31 |
| Sep | 30 |
| Oct | 31 |
| Nov | 30 |
| Dec | 31 |
5. Day Reference (Standard)
1 January 1900 = Monday
(This is commonly used in exams)
6. Finding the Day of the Week
Steps:
- Count total odd days till the given date
- Divide by 7
- Remainder gives the day
7. Important Exam Points
- Always check leap year or not
- February changes only in leap year
- Day calculation is based on odd days
- Repetition of calendar occurs after 28 years
8. Calendar Repetition
- Ordinary year → repeats after 6 or 11 years
- Leap year → repeats after 28 years
Top 25 Practice Questions – Calendar
Q1.
What day was 15 August 1947?
Q2.
What day will be 1 January 2030?
Q3.
If 1 January 2001 was Monday, what day was 31 December 2001?
Q4.
How many odd days are there in 5 leap years?
Q5.
What day of the week was 26 January 1950?
Q6.
If today is Monday, what day will it be after 45 days?
Q7.
What day was 1 March 2000?
Q8.
How many odd days are there in 100 years?
Q9.
What day will be 15 August 2025?
Q10.
If 1 January 2012 was Sunday, what day was 29 February 2012?
Q11.
What day was 31 December 1999?
Q12.
How many leap years are there between 2001 and 2100?
Q13.
What day will be 1 January 2040?
Q14.
If today is Friday, what day will it be after 100 days?
Q15.
What day was 2 October 1869?
Q16.
How many odd days are there in 300 years?
Q17.
What day was 14 November 1889?
Q18.
If 1 January 1990 was Monday, what day was 1 January 1991?
Q19.
What day will be 26 January 2026?
Q20.
How many days are there in 4 consecutive years starting from a leap year?
Q21.
What day was 15 August 2010?
Q22.
If 1 January 2020 was Wednesday, what day was 31 December 2020?
Q23.
What day will be after 280 days from Monday?
Q24.
What day was 7 July 2007?
Q25.
How many odd days are there in 50 years?
Answer
Answers – Calendar
Q1. Friday
Q2. Tuesday
Q3. Monday
Q4. 10 odd days
Q5. Thursday
Q6. Wednesday
Q7. Wednesday
Q8. 5 odd days
Q9. Friday
Q10. Wednesday
Q11. Friday
Q12. 24 leap years
Q13. Sunday
Q14. Sunday
Q15. Saturday
Q16. 1 odd day
Q17. Thursday
Q18. Tuesday
Q19. Monday
Q20. 1461 days
Q21. Sunday
Q22. Thursday
Q23. Monday
Q24. Saturday
Q25. 1 odd day