Identify Given Values and Relationship

Note the selling price and discount percentage given: $SP = \text{₹}720$ and $\text{Discount} = 20\%$. The relationship between Marked Price ($MP$) and Selling Price ($SP$) is given by $SP = MP \times \left(1 - \frac{D}{100}\right)$.

$SP = MP \times \left(1 - \frac{D}{100}\right)$

Substitute Values into the Formula

Substitute $SP = 720$ and $D = 20$ into the formula to form the equation: $720 = MP \times \left(1 - \frac{20}{100}\right)$.

$720 = MP \times \left(1 - \frac{20}{100}\right)$

Solve for Marked Price

Simplify the bracketed term to $0.8$ and solve for $MP$ by dividing $720$ by $0.8$, yielding $\text{₹}900$.

$MP = \frac{720}{0.8} = 900$