Which type of number is the number $\frac{22}{7}$? Is it rational or irrational?

For each question,select the proper option from the four options given to make the statement true: $(\sqrt{5}+\sqrt{3})(\sqrt{5}-\sqrt{3}) = \ldots \ldots \ldots$

Simplify the following:
$4 \sqrt{28} \div 3 \sqrt{7}$

Rationalise the denominator in each of the following:
$\frac{1}{7-4 \sqrt{3}}$

Find five rational numbers between $\frac{2}{7}$ and $\frac{2}{5}$.

Simplify the following:
$\frac{3}{\sqrt{8}} + \frac{1}{\sqrt{2}}$