Question

If $\sqrt{7}=2.646\mathrm{then}\frac{1}{\sqrt{7}}$ =?
(a) 0.375
(b) 0.378
(c) 0.441
(d) None of these

Answer 1

$\frac{1}{\sqrt{7}}=\frac{1}{\sqrt{7}}\times \frac{\sqrt{7}}{\sqrt{7}}=\frac{\sqrt{7}}{7}$
Given that
$$\begin{gathered} \sqrt{7}=2.646 \\ \mathrm{So},\frac{\sqrt{7}}{7}=\frac{2.646}{7}=0.378 \end{gathered}$$
Hence, the correct answer is option (b).