I posted this problem on a stale thread and it appeared that this problem did not get the attention it deserves. So, I decided to create a new thread for the problem.
Pls, is the anyone with a step by step solution to the problem below?

There is a substance which can be diluted to a number of solutions. The concentration of the substance is 35%, which can be diluted to 12% and 3% concentration.
If one part of the 35% concentration is added to eleven parts of distilled water, it will give a solution of 3% concentration and one part of 12% concentration added to three parts of distilled water will also give a solution of 3% concentration.
The problem is how to get the solution of 12% concentration from the 35% concentration. So, how many parts of distilled water will be added to one part of the 35% concentration to give the solution of 12% concentration?