Change the colour of random cells within a selection based on another cells value

Okay so im trying to change the text colour of random cells within a selection of cells based on another cells value.

For instance, i have 100 cells total each with the letter "O".

I have a separate cell which displays a % value based on the users input into another cell.

So, if this % value returns for example, 30%, then i want the text of 30 random cells within my selection of 100, to change colour to RED.

Is this possible? Forgive me if i haven't explained this very well, it does sound quite overwhelming.

You should post a sample worksheet, I have an idea how it may be possible but I have no inclination to make up my own sample sheet to test the theory :-)