2008 AMC 10A Problem 12

In a collection of red, blue, and green marbles, there are 25\% more red marbles than blue marbles, and there are 60\% more green marbles than red marbles. Suppose that there are r red marbles. What is the total number of marbles in the collection? \mathrm{(A)}\ 2.85r\qquad\mathrm{(B)}\ 3r\qquad\mathrm{(C)}\ 3.4r\qquad\mathrm{(D)}\ 3.85r\qquad\mathrm{(E)}\ 4.25r

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.