MCQ
Mark $(\checkmark)$ against the correct answer: $\frac{\sqrt[3]{128}}{\sqrt[3]{250}}=\ ?$
  • A
    $\frac{3}{5}$
  • $\frac{4}{5}$
  • C
    $\frac{2}{5}$
  • D
    None of these.

Answer

Correct option: B.
$\frac{4}{5}$

Resolving the numerator and the denominator into prime factors:
$\frac{\sqrt[3]{128}}{\sqrt[3]{250}}$
$=\sqrt[3]{\frac{128}{250}}$
$=\sqrt[3]{\frac{2\times8\times8}{2\times5\times5\times5}}$
$=\sqrt[3]{\frac{\not{2}\times8\times8}{\not{2}\times5\times5\times5}}$
$=\sqrt[3]{\frac{8\times8}{5\times5\times5}}$
$=\sqrt[3]{\frac{(2)^3\times(2)^3}{(5)^3}}$
$=\frac{2\times2}{5}$
$=\frac{4}{5}$

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