Profit and loss problem A shopkeeper allows a discount of 12.5% on the marked price of a certain article and makes a profit of 20%. If the article costs the shopkeeper Rs 210, then the marked price of the article will be?

You are given that : $$\begin{align} \operatorname{discounted} &= (100\%-12.5\%)\times\operatorname{marked} \\\\[1ex] \operatorname{discounted}&=(100\%+20\%)\times\operatorname{cost} \\\\[1ex] \operatorname{cost} &= \mathcal {Rs}\;120 \end{align}$$

Then clearly:

$$(100\%-12.5\%)\times\operatorname{marked}=(100\%+20\%)\times\mathcal {Rs}\;120$$

So it follows that: $$\therefore \operatorname{marked} = \dfrac{\Box}{\Box}$$