mark needs to make 15% sulfuric acid for a lab. how much sulfuric acid, and how much water does he need to use to make ^ liters of 15 % of sulfuric acid ?
If he is trying to make 15% from 15% then he doesn't need any water at all. He can just use the sulfuric acid directly.
If they want 10 liters, then he needs 10 liters of the sulfuric acid.
But.. is this really the question or did you mistype something?