Ashlyn is selling boxes of cookies for a fundraiser. if she raised $26 selling eight boxes, how much will she raise if she sells 40 boxes?

She'll make 130 dollars. How to do this type of thing:
you get the first number that you have so 26 then you do 26 divided by 8 for example and then you get 3.25 you do 3.25 x 40 and then you get 130. How to know that's right? Do 3.25 x 8 and see if that gets 26. Hope it helps!!