if marcus has three sections two of which are the same group then you take 100 and divide by 3 however since it cannot divide by 3 then the best possible answer is 99.9 so take this and dive it by 3 this gives 33.333333- now take that and multiply it by 2 since that would give it the same amount as two sections since the 33.33333- is 1/3 of the whole after multiplying it by 2 you get 66.66666- now this is 2/3 of the whole which represents the 2 blue sections and then subtracting the 99.99999- by the 66.666666- to find the 1/3 amount of 33.333333- which represents the purple