# solve this

Question:

If $\sqrt{7}=2.646$ then $\frac{1}{\sqrt{7}}=?$

(a) $0.375$

(b) $0.378$

(c) $0.441$

(d) None of these

Solution:

$\frac{1}{\sqrt{7}}=\frac{1}{\sqrt{7}} \times \frac{\sqrt{7}}{\sqrt{7}}=\frac{\sqrt{7}}{7}$

Given that

$\sqrt{7}=2.646$

So, $\frac{\sqrt{7}}{7}=\frac{2.646}{7}=0.378$

Hence, the correct answer is option (b).