Ok! I think I got it. This is what I concluded.
Total Balls=45
Green(G)=20
Red(R)=12
Yellow(Y)
P(G,R,Y)=(20/45) X (12/44) X (13/43)=(52/1419)
P(G,G,Y)=(20/45) X (19/44) X (13/43)=(247/4257)
P(G,Y,Y)=(20/45) X (13/44) X (12/43)=(52/1419)
(52/1419) + (247/4257) + (52/1419) = (13/99)
If this is...