Calendar
📅 Calendar Study Material for SSC CHSL Reasoning (With Emojis & Practice Questions)
What is a Calendar? 🗓️
A calendar is a chart that shows days, weeks, and months of a year. It helps us keep track of dates and plan events. In reasoning exams, calendar questions check your ability to calculate days, weeks, and leap years easily1.
Basic Structure of a Calendar 🏗️
- Ordinary Year: 365 days (e.g., 2019, 2021) ➡️ 1 odd day
- Leap Year: 366 days (e.g., 2020, 2024) ➡️ 2 odd days
- Leap year: Divisible by 4 (except century years, which must be divisible by 400)
Odd Days Concept 🤔
- Odd days: Extra days after complete weeks in a period.
- 31-day months: 3 odd days (Jan, Mar, May, Jul, Aug, Oct, Dec)
- 30-day months: 2 odd days (Apr, Jun, Sep, Nov)
- February: 0 odd days (ordinary), 1 odd day (leap)
| Month | Odd Days (Ordinary/Leap) |
|---|---|
| January | 3 |
| February | 0 / 1 |
| March | 3 |
| April | 2 |
| May | 3 |
| June | 2 |
| July | 3 |
| August | 3 |
| September | 2 |
| October | 3 |
| November | 2 |
| December | 3 |
Day Coding for Quick Calculation 🔢
| Day | Code |
|---|---|
| Sunday | 0 |
| Monday | 1 |
| Tuesday | 2 |
| Wednesday | 3 |
| Thursday | 4 |
| Friday | 5 |
| Saturday | 6 |
Leap Year Rules 🏆
- Year divisible by 4 = Leap year (e.g., 2016, 2020)
- Century year (ending with 00): Must be divisible by 400 to be a leap year (e.g., 2000 is leap, 1900 is not)1
Odd Days in Centuries 📈
| Century | Odd Days | Day of Week Ends On |
|---|---|---|
| 100 | 5 | Friday |
| 200 | 3 | Wednesday |
| 300 | 1 | Monday |
| 400 | 0 | Sunday |
- The cycle repeats every 400 years!
📝 Practice Questions with Detailed Solutions
Q1. What day of the week was 15th August 1947? 🇮🇳
Solution:
- Break into periods:
- 1600 years (0 odd days)
- 300 years (1 odd day)
- 46 years (from 1901 to 1946): 11 leap years, 35 ordinary years
- 11 × 2 + 35 × 1 = 22 + 35 = 57 odd days → 57 ÷ 7 = 1 odd day
- 1st Jan to 15th Aug 1947: 3 odd days
- Total odd days = 0 + 1 + 1 + 3 = 5
- 5 = Friday
Answer: Friday 🎉1
Q2. Today is Monday. What day will it be after 61 days?
Solution:
- 61 ÷ 7 = 8 weeks + 5 days
- Monday + 5 = Saturday
Answer: Saturday 🛍️1
Q3. Is 1900 a leap year?
Solution:
- 1900 is divisible by 4, but as a century year, it must be divisible by 400.
- 1900 ÷ 400 = 4.75 (not a whole number)
- So, not a leap year.
Answer: No, 1900 is not a leap year. 🚫1
Q4. Find the day of the week on 27th Dec 1985.
Solution:
- 1984 years: 1600 (0 odd) + 300 (1 odd) + 84 (0 odd)
- 11 months + 27 days: 361 days = 51 weeks + 4 odd days
- Total odd days = 1 + 4 = 5 → Friday
Answer: Friday 🥳1
Q5. Today is Wednesday. What will be the day after 91 days?
Solution:
- 91 ÷ 7 = 13 weeks (no extra days)
- The day repeats: Wednesday.
Answer: Wednesday 🔄1
Q6. Which year after 2009 will have the same calendar as 2009?
Solution:
- Sum odd days year-wise until total is a multiple of 7:
- 2009 (1), 2010 (1), 2011 (1), 2012 (2), 2013 (1), 2014 (1) = 7 odd days
- 2009 + 6 = 2015
Answer: 2015 🗓️1
Q7. Today is Friday. What day will it be after 59 days?
Solution:
- 59 ÷ 7 = 8 weeks + 3 days
- Friday + 3 = Monday
Answer: Monday 💼1
Q8. If today is Sunday, what will be the day on the 7777th day?
Solution:
- 7777 ÷ 7 = 1111 weeks (no extra days)
- The day repeats: Sunday
Answer: Sunday ☀️1
Q9. Today is Saturday. What will be the day after 86 days?
Solution:
- 86 ÷ 7 = 12 weeks + 2 days
- Saturday + 2 = Monday
Answer: Monday 🏫1
Q10. Today is Monday. What will be the day after 32 days?
Solution:
- 32 ÷ 7 = 4 weeks + 4 days
- Monday + 4 = Friday
Answer: Friday 🎊1
Quick Tips & Tricks 🧠
- Remember the odd days for each month for fast calculation.
- For century years, check divisibility by 400 for leap years.
- Use day codes for quick addition.
- Practice with real dates to get faster!
Happy Learning & Practicing! 🚀 Use these concepts and tricks to ace calendar questions in SSC CHSL Reasoning!
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