Question

A person's birthday on 21\(^{st}\) July was on Wednesday. On what day will the Christmas fall in the same year?

• A. Monday
• B. Tuesday
• C. Wednesday
• D. Saturday

Hint:

To quickly calculate odd days for months, remember: 31-day months have 3 odd days (31 mod 7 = 3), and 30-day months have 2 odd days (30 mod 7 = 2).

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We are given that the 21st of July in a particular year was a Wednesday. We need to find the day of the week for Christmas, which is on the 25th of December of the same year. The question is noted to be potentially incorrect, so we must rely on our calculation.
Step 2: Key Formula or Approach:
The method is to count the total number of days between the two dates and then find the number of "odd days". An odd day is a day remaining after dividing the total number of days by 7. The day of the week for the final date will be the starting day plus the number of odd days.
Step 3: Detailed Explanation:
Let's count the number of days from 21st July to 25th December.

Days remaining in July = 31 - 21 = 10 days
Days in August = 31 days
Days in September = 30 days
Days in October = 31 days
Days in November = 30 days
Days in December = 25 days Total number of days = 10 + 31 + 30 + 31 + 30 + 25 = 157 days.
Now, we find the number of odd days by dividing the total days by 7:
\[ \frac{157}{7} = 22 \text{ weeks and } 3 \text{ days remainder} \] So, there are 3 odd days.
The day of the week for Christmas will be Wednesday + 3 odd days.
Wednesday + 1 day = Thursday
Wednesday + 2 days = Friday
Wednesday + 3 days = Saturday.
Step 4: Final Answer:
The calculated day for Christmas is Saturday.