The solute dissociates slightly in the solvent. how will the slight dissociation affect the reported

The solute dissociates slightly in the solvent. The slight dissociation can be shown can be shown in the solubility product constant. An example is when the reported If a cell is placed inside a solution that has a higher concentration of solute than on the inside of the cell, the movement of water will move out of the cell, causing it to shrivel. The movement is affected on how much concentration is with the system and surrounding. It moves from a higher concentration to a lower concentration of solute. 

You would do 1500/4 and the answer is 375