Since statement (2) does not state A and B are independent events, I have assumed the following:

a - Represents probability that only event A occurs

b - Represents probability that only event B occurs

c - Represents probability that both events A&B occur

d - Represents probability that neither A nor B occurs

Therefore, a+b+c+d = 1

a+c=0.4, b+c=0.8 and according to statement (2) d=0.32

We want to find the probability that only A occurs and B does not occur i.e "a"

a+b+2c = 1.2

a+b+c = 1-d = 0.68

c=0.52

Now a+c = 0.4 Therefore a= -0.12 But, how can a probability be NEGATIVE?

Bunuel Please help! I think the question is wrong...