Say that you owned a restaurant, and you were required to buy a shipment of food. The problem is that you don't know which way is an easier way of ordering the food; Ratios or percentages? Well, here is what I believe would be very suitable to help in this situation.
First, you need to think; which would work more affectively? I believe that using percentages would be more affective because it's easier to do. For example, you can say you're ordering 100% amount of food. What percentage/fraction of that 100% would you want to be apples? So, then you decide what percentage of apples you would want from 100%. 100% - 15% = 85%, so now you have 85% amount of food left. This is why I think that the percentage method is more affective, because it makes it very simple and an understandable way of doing this.