Question 74476
8 liters of 40% solution contains {{{8*.40}}} or 3.2 liters of acid.

This 3.2 liters represents 10% of the final solution, so the volume of that solution is {{{3.2/.10}}} or 32 liters of solution.

To go from 8 liters to 32 liters you add 24 liters of water.