Weekday by offset from a known Sunday: Suresh was born on October 4, 1999. Shashikanth was born 6 days earlier. If Independence Day (Aug 15, 1999) was Sunday, which day was Shashikanth born?

Difficulty: Medium

Correct Answer: Tuesday

Explanation:


Introduction / Context:
We are given a reference weekday (Aug 15, 1999 = Sunday) and need to find the weekday for a later September date (6 days before Oct 4). By counting the total days forward and reducing modulo 7, we can determine the resulting weekday step from Sunday.


Given Data / Assumptions:

  • Suresh: Oct 4, 1999 ⇒ Shashikanth = Sep 28, 1999 (6 days earlier).
  • Aug 15, 1999 = Sunday.
  • September has 30 days; August has 31.


Concept / Approach:
Compute the number of days from Aug 15 to Sep 28: days remaining in Aug plus days up to Sep 28; reduce modulo 7 and step the weekday forward from Sunday.


Step-by-Step Solution:

Aug 15 → Aug 31: 16 days.Sep 1 → Sep 28: 28 days.Total = 44 days ≡ 2 (mod 7).Sunday + 2 = Tuesday.


Verification / Alternative check:
Breaking 44 as 35 + 9 ⇒ +0 + 2 = +2; consistent.


Why Other Options Are Wrong:
Wednesday/Monday/Sunday correspond to +3/+1/+0 steps, not +2.


Common Pitfalls:
Mistakes in counting the days in each month; always reduce modulo 7.


Final Answer:
Tuesday

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