CAT 2025 Slot 1 QA Question 2: A container holds 200 litres of a solution of acid and water, having 30% acid by volume. Atul replaces 20% of this solution with water, then replaces 10% of the resulting solution with acid, and final

Question

A container holds 200 litres of a solution of acid and water, having 30% acid by volume. Atul replaces 20% of this solution with water, then replaces 10% of the resulting solution with acid, and final

Accepted Answer

The total volume remains 200 litres after each replacement, so we can track only the amount of acid.
Initial acid = $30\% 	imes 200 = 60$ litres

First, 20% of the solution is removed and replaced with water.
Volume removed = $20\% 	imes 200 = 40$ litres
Acid removed = $30\% 	imes 40 = 12$ litres