(b) A and B are mutually exclusive events such that P(A) = 1/2 and P(B) = 1/3 and P (AU B) = 1/4. What is the probability of P(A Ո B)?

 The probability of the union of two mutually exclusive events A and B is given by the sum of their individual probabilities:

\[ P(A \cup B) = P(A) + P(B) \]

However, in this case, you have mentioned that \(P(A \cup B) = \frac{1}{4}\), and A and B are mutually exclusive events. For mutually exclusive events, the probability of their union is zero (\(P(A \cup B) = 0\)) because if one event occurs, the other cannot.

So, in this case, \(P(A \cup B) = 0\). The probability of the union of mutually exclusive events is always zero.