If $\sqrt{2^{n}} = 64$,then find the value of $n$.

Twenty-one times a positive number is less than its square by $100$. The value of the positive number is:

What approximate value will come in place of the question mark $(?)$ in the given equation? (You are not expected to calculate the exact value)
$24.98^{2} \times \frac{16.02^{2}}{(7.98 \times 15.04)} \times 38.93 = 130 \times ?^{2}$

If $a = \sqrt{2} + 1$ and $b = \sqrt{2} - 1,$ then the value of $\frac{1}{a + 1} + \frac{1}{b + 1}$ will be

The value of $2.1\overline{36}$ is

If $\frac{144}{0.144} = \frac{14.4}{x}$,then the value of $x$ is