A breeder of guinea pigs has 1 male and 2 females in a red cage, and two males and one female in a blue cage. A visiting child picks up a guinea pig from the red cage with his right hand and a guinea pig from the blue cage with his left hand and then puts each guinea pig into the wrong cage. What is the probability that each cage will now have 3 animals of the same sex?
red: P(male) = 1/3
blue: P(female) = 1/3
so, 1/9 that he will get both the needed gp's.