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Assertion (A) : A relation R on… (Class 12 Maths 2026, Q19)

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MathsCBSE Class 12 · Board exam 2026, set 65/5/1 · 1 mark · Assertion-reason

CBSE Class 12 Mathematics 2026: question 19

Set in the CBSE Class 12 board exam of 2026, paper 65/5/1, section A, question 19, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q19 · 1 mark · Assertion-reasonCompetency-basedRelations and Functions

Assertion (A) : A relation R on the set {1, 2, 3} defined as R = {(1, 1), (1, 2), (2, 1), (2, 2), (3, 3)} is an equivalence relation.

Reason (R) : A relation that is reflexive, symmetric and transitive is an equivalence relation.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 65/5/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Check each of the three properties.

Hint 2

Is R the definition used?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. R contains (1,1),(2,2),(3,3): reflexive; (1,2),(2,1) both present: symmetric; all compositions stay in R: transitive. So A true.

    ½ mark

  2. R is the definition of equivalence relation and explains A. Option (A).

    ½ mark

Answer: Option (A)

Where the marks are

  • Checks R reflexive, symmetric, transitive (½ mark)
  • Recognises R explains A (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Relations and Functions, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 65/5/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.