A shopkeeper marks the price of an article $25\%$ above its cost price. After allowing a $10\%$ discount on the marked price, the article is sold for $\text{₹}720$. What is the difference (in $\text{₹}$) between the cost price and marked price of the article?

Let the cost price (CP) of the article be $100x$.The shopkeeper marks the price $25\%$ above the cost price:
$$\text{Marked Price (MP)}=100x+25\%\text{ of }100x=125x$$
A discount of $10\%$ is given on the marked price:
$$\text{Discount}=10\%\text{ of }125x=12.5x$$
Therefore, the selling price (SP) is:
$$\text{SP}=\text{MP}-\text{Discount}=125x-12.5x=112.5x$$
Given that the article is sold for $\text{₹}720$:
$$112.5x=720$$
$$x=\frac{720}{112.5}=\frac{7200}{1125}=6.4$$
We need to find the difference between the cost price and the marked price:
$$\text{Difference}=\text{MP}-\text{CP}=125x-100x=25x$$
Substituting the value of $x$:
$$\text{Difference}=25\times 6.4=\text{₹}160$$