Bhavin has his birthday on Monday, 29th May. In the same year, on what day of the week will Rachit's birthday fall if Rachit was born on 17th November?

Introduction / Context:
This is a calendar and day of the week problem. You are told that Bhavin's birthday on 29 May falls on a Monday, and you must determine the day of the week on which Rachit's birthday on 17 November of the same year falls. Questions like this test your understanding of how days shift as you move forward through the calendar, taking into account the number of days in each month. Because both dates are in the same year and after February, leap year complications do not affect the difference between these two dates.

Given Data / Assumptions:

• Bhavin's birthday: 29th May, which is a Monday.
• Rachit's birthday: 17th November of the same year.
• We assume the usual Gregorian calendar with month lengths: May 31, June 30, July 31, August 31, September 30, October 31, November 30.
• We only need the offset in days between 29 May and 17 November modulo 7.

Concept / Approach:
The key idea is to count the total number of days between the two given dates and then take this total modulo 7, because the days of the week repeat every 7 days. If we know that a certain day is Monday and we move forward by a certain number of days, dividing that number by 7 and taking the remainder tells us how many steps forward we move in the weekly cycle. A positive remainder r means the day advances by r positions from Monday.

Step-by-Step Solution:
Step 1: Count the days remaining in May after 29th. May has 31 days. From 30 May to 31 May there are 2 days. Step 2: Count the days in each full month from June to October. June: 30 days. July: 31 days. August: 31 days. September: 30 days. October: 31 days. Step 3: Count the days in November up to and including 17th. From 1 November to 17 November is 17 days. Step 4: Add all these day counts to get the total number of days from 29 May to 17 November. Total = 2 (May) + 30 (June) + 31 (July) + 31 (August) + 30 (September) + 31 (October) + 17 (November). Now compute: 2 + 30 = 32, 32 + 31 = 63, 63 + 31 = 94, 94 + 30 = 124, 124 + 31 = 155, 155 + 17 = 172. So there are 172 days from 29 May to 17 November. Step 5: Reduce 172 modulo 7. 7 * 24 = 168, and 172 - 168 = 4, so 172 ≡ 4 (mod 7). Step 6: Starting from Monday, move forward 4 days in the week. Monday + 1 day = Tuesday. Monday + 2 days = Wednesday. Monday + 3 days = Thursday. Monday + 4 days = Friday.

Verification / Alternative check:
You can verify by smaller blocks. After 7 days from 29 May, the day again becomes Monday. After 14, 21, and so on, it repeats. Only the remainder after dividing by 7 shifts the weekday. Because 172 divided by 7 leaves a remainder of 4, the weekday must move ahead by exactly 4 positions. This is independent of whether the year is a leap year, because both dates fall after February and the extra day in February would affect both dates equally in terms of relative distance from the start of the year.

Why Other Options Are Wrong:
Options Saturday, Wednesday, and Sunday correspond to advances of 5, 2, and 6 days from Monday respectively. None of these agree with the actual remainder of 4 when 172 is divided by 7. Only Friday matches the calculated offset, so the other options contradict the strict arithmetic of the calendar difference and must be rejected.

Common Pitfalls:
Common mistakes include miscounting the days in one of the months, especially June or September, or counting from 29 May incorrectly by including or excluding a boundary day in the wrong way. Another pitfall is to attempt to handle the problem month by month without converting everything into an exact total of days. Using a clear, step by step day count and then reducing modulo 7 is the most reliable approach.

Final Answer:
Rachit's birthday on 17th November in the same year falls on Friday.