Given that Monday fell on April 4, 1988, what was the day of the week on November 3, 1987?

Difficulty: Medium

Correct Answer: Tuesday

Explanation:

Introduction / Context:We can move backward from a known weekday using month lengths to find a previous date's weekday.

Given Data / Assumptions:

  • April 4, 1988 = Monday.
  • 1988 is a leap year; we are moving back into 1987 (a common year).

Concept / Approach:Step back month by month, applying the correct month lengths and mod 7 arithmetic to get the weekday for November 3, 1987.

Step-by-Step Solution (sketch):From Apr 4, 1988 to Jan 1, 1988: subtract offsets (Mar 31, Feb 29, Jan 31) with leap-year February.Then move back across 1987's months to Nov 3, 1987 using common-year month lengths.Carrying the mod 7 arithmetic yields Tuesday.

Verification / Alternative check:Independent weekday algorithms confirm November 3, 1987 was Tuesday.

Why Other Options Are Wrong:Other weekdays do not match the backward count under correct month lengths.

Common Pitfalls:Forgetting that 1988 is a leap year (Feb has 29 days); miscounting days when crossing the year boundary.

Final Answer:Tuesday

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