Solve this :

38. A and B are events such that P(A) = 1/4, P(B) = 1/2 & P(A & B) = 1/8. Find :
(i) P(A & B)                     (ii) P(not A & not B)
 

i) P(A or B) = P(A) + P(B) - P(A and B)
                 = 1/4 + 1/2 - 1/8
                 = 5/8.
ii)  BY DE MORGAN'S LAW:--
P(A' and B')=P(A and B)'
THEREFORE:
P(not A and not B)= 1 - P(A or B)
                              = 1 - 5/8
                             = 3/8.