Question: A cage contains six rats, two of them white (W) and four of them black (B); a second cage
contains four rats, two white and two black; and a third cage contains five rats, three white
and two black. If one rat is selected randomly from each cage, what is the probability that exactly two of the three will be white?  Edit

Answer: probability that exactly two of the three will be white=
P(1st white,2nd white,3rd black)+
P(1st white, 2nd black, 3rd white)+
P(1st black, 2nd white , 3rd white)
= P(w1)*P(W2)*P(B3)+P(w1)*P(B2)*P(W3)
+P(B1)*P(W2)*P(W3)
=(2/6)*(2/4)*(2/5)+(2/6)*(2/4)*(3/5)
+(4/6)*(2/4)*(3/5)
=0.367(Ans.)  Edit