Hi Scott,

The desired 2000 ml is 25% sulfuric acid so the amount of acid in this mixture is $25\% \mbox{ of } 2000$ or $\large \frac{25}{100} \times 2000$ ml. Suppose that you pour $S$ ml of the $96\%$ solution into a container then this mixture contains $\large \frac{96}{100} \times S$ ml of sulfuric acid. This has to be $\frac{25}{100} \times 2000$ ml. Solve for $S.$ Fill the container up to the 2000 ml mark and you have what you need.

Penny