Time-sequence / date intersection: Adi remembers Ana’s birthday is after 20th September but before 23rd. Father remembers it is after 21st and before 24th September. Determine Ana’s correct date of birth.

Introduction / Context:
Two interval clues must be intersected to find a unique date. “After” and “before” are strict inequalities (exclude endpoints).

Given Data / Assumptions:

• Adi: 20 < date < 23 ⇒ {21, 22}.
• Father: 21 < date < 24 ⇒ {22, 23}.

Concept / Approach:
Take the intersection of the two candidate sets to find the only date satisfying both memories.

Step-by-Step Solution:

Verification / Alternative check:
22 is indeed after 20 and before 23, and after 21 and before 24.

Why Other Options Are Wrong:
21 contradicts Father’s “after 21”; 23 contradicts Adi’s “before 23”; 24 is out of both ranges.

Common Pitfalls:
Treating “after/before” as inclusive bounds.

Final Answer:
22nd September