A total of two variables with a greater or lesser percentage

Hi there everyone, Newbie here.

So what I am trying to do is get a total of two different collumns which have lesser than or greater than percentages.

For instance, there is collumn 1 which is a number (10 for example) and this number cannot be more than 4%.
The second collumn, (20 for example) must be less than 15%.

So the total will be no more than 4% of collumn one as well as no less than 15% of collumn two, to make a total.

What formula should I use to do this? I am completely stumped.

Any help would be greatly appreciated, thanks guys.