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Mathematics

Assertion (A) : 4121253=135\sqrt[3]{4\dfrac{12}{125}} = 1\dfrac{3}{5}

Reason (R) : If p and q are two whole numbers (p ≠ 0), then pq3=p3q3\sqrt[3]{\dfrac{p}{q}} = \dfrac{\sqrt[3]p}{\sqrt[3]q}.

  1. Both A and R are correct, and R is the correct explanation for A.

  2. Both A and R are correct, and R is not the correct explanation for A.

  3. A is true, but R is false.

  4. A is false, but R is true.

Cube & Cube Roots

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Answer

If p and q are two whole numbers (p ≠ 0), then pq3=p3q3\sqrt[3]{\dfrac{p}{q}} = \dfrac{\sqrt[3]p}{\sqrt[3]q}.

This is a fundamental property of radicals.

So, reason (R) is true.

Solving,

41212534×125+121253500+12125351212535123125385135\Rightarrow \sqrt[3]{4\dfrac{12}{125}}\\[1em] \Rightarrow \sqrt[3]{\dfrac{4 \times 125 + 12}{125}}\\[1em] \Rightarrow \sqrt[3]{\dfrac{500 + 12}{125}}\\[1em] \Rightarrow \sqrt[3]{\dfrac{512}{125}}\\[1em] \Rightarrow \dfrac{\sqrt[3]{512}}{\sqrt[3]{125}}\\[1em] \Rightarrow \dfrac{8}{5}\\[1em] \Rightarrow 1\dfrac{3}{5}

So, assertion (A) is true and reason (R) clearly explains assertion.

Hence, option 1 is the correct option.

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