A survey for washing-up liquid revealed that $\frac{2}{3}$ of all customers bought Jinx and $\frac{1}{3}$ of customers bought Kleenz. Nobody bought both.

After an advertising campaign for Kleenz, the only change in sales was that $\frac{1}{4}$ of the people who had bought Jinx were now buying Kleenz instead.

What fraction of customers now buy Kleenz?


If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.