Answer:
Tonicity is a measure of the concentration of solute particles in a solution compared to another solution. It is used to describe the effects of a solution on a cell.
If a cell is placed in a 15% solute solution and the cell shrinks, it means that the solution is hypertonic to the cell. Hypertonic solutions have a higher concentration of solute particles than the inside of the cell, which causes water to move out of the cell by osmosis. As water leaves the cell, it shrinks.
So, in this case, the tonicity of the 15% solution is hypertonic.