Rewrite terms with fractional exponents.
$$ \frac{\sqrt{a\sqrt{b}}}{\sqrt{ab}} = \frac{(ab^{\frac{1}{2}})^{\frac{1}{2}}}{(ab)^{\frac{1}{2}}} $$
Using a few exponent rules,
$$ \frac{(ab^{\frac{1}{2}})^{\frac{1}{2}}}{(ab)^{\frac{1}{2}}} = \frac{a^{\frac{1}{2}}b^{\frac{1}{2}\cdot\frac{1}{2}}}{a^{\frac{1}{2}}b^{\frac{1}{2}}}$$
$$ = \frac{\cancel{a^{\frac{1}{2}}}b^{\frac{1}{4}}}{\cancel{a^{\frac{1}{2}}}b^{\frac{1}{2}}} = \frac{b^{\frac{1}{4}}}{b^{\frac{1}{2}}} $$
$$ = b^{\frac{1}{4}-\frac{1}{2}} = b^{-\frac{1}{4}}$$
$$ = \boxed{\frac{1}{\sqrt[4]{b}}} $$
Looking at the individual factors underneath the square roots:
$$ \frac{\sqrt{a\sqrt{b}}}{\sqrt{ab}} = \frac{\cancel{\sqrt{a}}\cdot\sqrt{\sqrt{b}}}{\cancel{\sqrt{a}}\cdot\sqrt{b}} $$
$$ = \frac{\sqrt{\sqrt{b}}}{\sqrt{b}} $$
Like the first approach, the next part is much easier to simplify with fractional exponents.
$$ = \frac{\sqrt{\sqrt{b}}}{\sqrt{b}} = \frac{(b^\frac{1}{2})^{\frac{1}{2}}}{b^{\frac{1}{2}}}$$
$$ = \frac{b^{\frac{1}{4}}}{b^{\frac{1}{2}} } $$
$$ = b^{\frac{1}{4}-\frac{1}{2}} = b^{-\frac{1}{4}}$$
$$ = \boxed{\frac{1}{\sqrt[4]{b}}} $$