The inner circle circumference is 18 and the outer is 4
If you have 3/5 marbles and you got 4/3more marbles then all you have to do is:3/5 x 3/3 and get 9/15.For 4/3 you multiply 4/3 x 5/5 and get 20/15.You simplify this and get 1 5/15.Now all you do is add them and get 1 14/15. Hope this helped you :-).
1turn = 360 half a turn is 180
360+180=540