Theory:

1. Conversion of Percent into Fraction

To convert a percent into a fraction, divide it by $$100$$ and remove the "$$\%$$" sign.
Let, $$a$$$$\%$$ $$=$$ $\frac{a}{100}$ [Percent $$=$$ Fraction]
Example:
(i) $52%$ $$=$$ $\frac{52}{100}$

(ii) $40%$ $$=$$ $\frac{40}{100}$
Note: Percent is a fraction with denominator $$100$$, and the numerator of this fraction is called Rate Percent.

2. Conversion of Fraction into Percent
To convert any fraction to percent, multiply it by 100 and put the percent sign($$\%$$).
Let, $\frac{a}{b}=\left[\frac{a}{b}×100\right]%$
(fraction)  (percent)
Example:
$\frac{9}{10}=\left[\frac{9}{10}·100\right]%$ $$=$$ 90$$\%$$

3. Conversion of fraction into Percent
To convert the percent into ratio, first change it to a fraction by dividing it by $$100$$ and remove the percent ($$\%$$) sign. Finally, reduce the obtained fraction to the simplest form.
Example:
(i) $$25$$$$\%$$

$$= 25/100$$

$$= 1/4$$

$$= 1:4$$

(ii) $$0.4$$$$\%$$

$$= 0.4/100$$

$$= 4/1000$$

$$= 1/250$$

$$= 1:250$$