In a school there are 7 subjects in class Xth. Each subject is taught on seven…

2024

In a school there are 7 subjects in class Xth. Each subject is taught on seven different days of the week. The subjects are English, Hindi, Maths, Biology, History, Geography, and Chemistry. English class is held on Sunday. Hindi class is held after maths and biology class. History, Geography and Chemistry class is held on consecutive days, however not in same order.

Which statement is true?

  1. A.

    Hindi class is held after Geography class

  2. B.

    English, History, and Chemistry class is held on consecutive days

  3. C.

    The chemistry class can be held latest by Saturday

  4. D.

    There is no class on Monday

Attempted by 6 students.

Show answer & explanation

Correct answer: C

Answer: The chemistry class can be held latest by Saturday.

Given:

  • English is on Sunday.

  • History, Geography and Chemistry occupy three consecutive days (in some order).

  • Hindi is scheduled after both Maths and Biology (so Hindi must come after two other days).

Key observation:

  • The three-day block for History, Geography and Chemistry cannot include Sunday because English is already on Sunday and those three are distinct subjects. Therefore the three-day block must lie within Monday–Saturday.

  • As a result, Chemistry cannot be on Sunday; the latest possible day for Chemistry is Saturday.

Why the other statements are not necessarily true:

  • The statement that Hindi is held after Geography is not forced by the rules. Depending on how you place the three-day block and the Maths and Biology days, Hindi can be either before or after Geography. Example where Hindi is after Geography: Sun: English; Mon: Geography; Tue: History; Wed: Chemistry; Thu: Maths; Fri: Biology; Sat: Hindi. Example where Hindi is before Geography: Sun: English; Mon: Maths; Tue: Biology; Wed: Hindi; Thu: Geography; Fri: History; Sat: Chemistry.

  • The statement that English, History, and Chemistry are on consecutive days is impossible because the three-day consecutive block belongs to History, Geography and Chemistry and cannot include Sunday (English).

  • The statement that there is no class on Monday contradicts the fact that seven subjects are held on seven different days, so every day has a class.

Conclusion: The only statement that must be true in all valid arrangements is that Chemistry can be held at the latest on Saturday.

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