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Q.Assertion (A) : Solution set of inequality ∣3x−2∣≤12|3x - 2| \leq \dfrac{1}{2}, x∈Rx \in R is [12,56]\left[\dfrac{1}{2}, \dfrac{5}{6}\right]. Reason (R) : ∣x−a∣≤r⇔x≤a−r|x - a| \leq r \Leftrightarrow x \leq a - r or x≥a+rx \geq a + r. (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is notnot the correct explanation of the Assertion (A). (C) Assertion (A) is true, but Reason (R) is false. (D) Assertion (A) is false, but Reason (R) is true.

CBSECBSE Class XII Board 2025MCQ· 1mImportance★★★★★est
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The Assertion's solution set [12,56][\tfrac12,\tfrac56] is correct, but the Reason misstates the modulus rule (it describes ≥\ge, not ≤\le), so (C).

Correct rule: ∣x−a∣≤r  ⟺  a−r≤x≤a+r|x-a|\le r \iff a-r \le x \le a+r (a closed interval), whereas ∣x−a∣≥r  ⟺  x≤a−r or x≥a+r|x-a|\ge r \iff x\le a-r \text{ or } x\ge a+r.

  1. Solve the Assertion: ∣3x−2∣≤12  ⟺  −12≤3x−2≤12|3x-2|\le \tfrac12 \iff -\tfrac12 \le 3x-2 \le \tfrac12.
  2. Add 2 throughout: 32≤3x≤52\tfrac32 \le 3x \le \tfrac52.
  3. Divide by 3: 12≤x≤56\tfrac12 \le x \le \tfrac56, i.e. solution set [12,56]\left[\tfrac12,\tfrac56\right] — Assertion is true. …

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