The cost of 1 litre of milk is ₹ $42\dfrac{3}{5}$. Find the cost of $12\dfrac{1}{2}$ litres of milk.

Given, the cost of 1 litre of milk = ₹ $42\dfrac{3}{5}$

The cost of $12\dfrac{1}{2}$ litres of milk :

$= ₹42\dfrac{3}{5} \times 12\dfrac{1}{2}\\[1em] = ₹\dfrac{213}{5} \times \dfrac{25}{2}\\[1em] = ₹\dfrac{213}{2} \times \dfrac{25}{5}\\[1em] = ₹\dfrac{213}{2} \times 5 \\[1em] = ₹\dfrac{1065}{2}\\[1em] = ₹ 532\dfrac{1}{2}.$

Hence, the cost of $12\dfrac{1}{2}$ litres of milk = ₹ $532\dfrac{1}{2}$.