Data Sufficiency — Day of the week for a visit: On which day did Hitesh visit the zoo? Statements: I. Hitesh did not visit on Tuesday or Thursday. II. Hitesh visited the zoo two days before his mother reached his house, and she arrived the day after Monday.
Correct Answer: II alone is sufficient while I alone is not sufficient
Introduction / Context:We are to determine the exact weekday of Hitesh’s zoo visit. This is a timeline/offset problem framed in data sufficiency style, where specific offsets from a known reference day provide the unique answer.
Given Data / Assumptions:
- I: Excludes Tuesday and Thursday only.
- II: Mother arrives “the day after Monday,” i.e., Tuesday; Hitesh visited two days earlier.
- Days of the week follow the usual order: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday.
Concept / Approach:Translate the verbal offsets into exact days. If one statement pinpoints a unique day, it is sufficient by itself. If not, see whether combining statements is necessary.
Step-by-Step Solution:From II: Mother arrives on Tuesday.Two days before Tuesday is Sunday (Tuesday − 2 → Monday − 1 → Sunday).Therefore, Hitesh visited the zoo on Sunday.Statement I alone only rules out two days and cannot fix a unique day.
Verification / Alternative check:Cross-check with Statement I: Sunday is neither Tuesday nor Thursday, so there is no conflict. II alone already gives a unique answer, confirming sufficiency.
Why Other Options Are Wrong:
- I alone: Multiple days remain possible.
- Either / Both: II alone suffices; both are not required.
- Neither: Incorrect because II works.
Common Pitfalls:
- Miscalculating offsets (some mistakenly say Monday).
- Thinking “the day after Monday” could be ambiguous—it is Tuesday.
Final Answer:II alone is sufficient while I alone is not sufficient