Where b = big, m = medium, s= small

10b + 10m + 10s = 7.08333    - 1
            20s = 0.8333     - 2
10b + 20m       = 8.333      - 3
      20m       = 3.333      - 4

From 3 & 4 we can say

10b = 5     

From 4 we can say

10m = 1.6666

From 2 we can say 

10s = 0.41666