ABC26GN1912 · Surds and Indices

Subject: General Aptitude · Chapter: Surds and Indices · Exam: 2006 · Marks: · Difficulty:

The value of $(0.03125)^{-\frac{2}{5}}$ is
(a)4
(b)9
(c)12
(d)31.25
Answer
Answer (as printed): A
Explanation
$$\begin{aligned} (0.03125)^{-\frac{2}{5}} & =\left[(0.5)^{5}\right]^{-\frac{2}{5}}=0.5^{\left[5 \times\left(-\frac{2}{5}\right)\right]}=(0.5)^{2-} \\ & =\frac{1}{(0.5)^{2}}=\frac{1}{0.25}=4 \end{aligned}$$

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