Q. 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.
(d) 12th July is not a Sunday if the year is a leap year.
Correct Answer: (c) 12th July is a Sunday if the year is a leap year.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
Problem: Finding the day of week in July if 12th January is a Sunday
Given:
– 12th January is a Sunday
– Need to determine if 12th July is a Sunday in a leap year
Solution:
1. Count days from 12th January to 12th July:
– Remaining days in January = 31 – 12 = 19 days
– February (leap year) = 29 days
– March = 31 days
– April = 30 days
– May = 31 days
– June = 30 days
– July (till 12th) = 12 days
2. Total days = 19 + 29 + 31 + 30 + 31 + 30 + 12 = 182 days
3. Calculate odd days:
– 182 ÷ 7 = 26 weeks + 0 days
– 0 odd days means same day as start
4. Since 12th January was Sunday:
– 0 odd days means 12th July will also be Sunday
Therefore, in a leap year, 12th July will be a Sunday.
