### Theory:

The reduction in market price to increase the sale or to dispose of old goods is known as a discount.
Usually, discounts are express as a percentage of the marked price.

The customer or buyer pays the difference between the marked price and the discounted price.

Thus, we have $\mathit{Discount}\phantom{\rule{0.147em}{0ex}}=\phantom{\rule{0.147em}{0ex}}\mathit{Marked}\phantom{\rule{0.147em}{0ex}}\mathit{price}\phantom{\rule{0.147em}{0ex}}×\mathit{Discount}\phantom{\rule{0.147em}{0ex}}\mathit{percentage}$.
Example:
Suresh went to purchase a shirt which is discounted like 9 $$\%$$ of it's marked price which is $$₹$$209.

Can you find how much amount is discounted for the shirt that he bought?

We can apply the above formula to find the discount amount.

$\begin{array}{l}\mathit{Discount}\phantom{\rule{0.147em}{0ex}}\mathit{amount}=\phantom{\rule{0.147em}{0ex}}209×9%\\ \\ \mathit{Discount}\phantom{\rule{0.147em}{0ex}}\mathit{amount}=\phantom{\rule{0.147em}{0ex}}209×\frac{9}{100}\\ \\ \mathit{Discount}\phantom{\rule{0.147em}{0ex}}\mathit{amount}=\frac{1881}{100}\\ \\ \mathit{Discount}\phantom{\rule{0.147em}{0ex}}\mathit{amount}=₹\phantom{\rule{0.147em}{0ex}}18.81\end{array}$

Therefore $$₹$$18.81 amount has been discounted from the marked price of 209.
Now can you calculate for how amount Suresh bought that shirt?

Just subtract the marked price by the discounted amount.

That is, $209-18.81$ $$=$$ 190.19.

Therefore he bought the shirt for $$₹$$190.19.