Calendars — month roll-over day logic If 1st October is a Sunday, then on which day will 1st November fall?

Introduction / Context:
This question checks calendar arithmetic: how weekdays shift when one month rolls into the next. October has 31 days, so the weekday for the 1st of the following month moves forward by 31 mod 7 days.

Given Data / Assumptions:

• 1 October is a Sunday.
• October has 31 days.
• Weekdays cycle every 7 days.

Concept / Approach:
When a month has 31 days, the weekday advances by 3 days (because 31 = 28 + 3, and 28 is a full 4-week cycle).

Step-by-Step Solution:
Start day: Sunday.Advance by 31 days ⇒ net shift = 31 mod 7 = 3 days.Sunday + 3 days ⇒ Monday (1), Tuesday (2), Wednesday (3).

Verification / Alternative check:
List a short run of dates: 1 Oct (Sun), 8 Oct (Sun), 15 Oct (Sun), 22 Oct (Sun), 29 Oct (Sun) → 30 Oct (Mon) → 31 Oct (Tue) → 1 Nov (Wed).

Why Other Options Are Wrong:
Monday/Tuesday/Thursday do not reflect the +3-day rule for a 31-day month.

Common Pitfalls:
Forgetting that 30-day months shift +2, while 31-day months shift +3.

Final Answer:
Wednesday