How does finding the area of a rectangle or square with the unit squares related to using the formula to find an area

So you have 6 marbles and 6 is twice as many as however many green marbles you have. The "five times more blue marbles than red marbles" is used to confused you, it's irrelevent to solving the problem.  For the answer, if you use the opposite equation of multiplication, division, it'll give you the answer. I believe doing that is called inverse something, but I can't remember atm ꒪▿꒪

So I'm quite certain it's C.