Answer the following questions briefly, justifying each statement wherever necessary.
a. (i) Define the union and the intersection of two events A and B in the context of probability theory.
b. (ii) State the rule that relates P(A∪B), P(A), P(B) and P(A∩B) for any two events A and B taken from the same sample space.
c. (iii) Using the rule stated in part (ii), show that if the events A and B are mutually exclusive then P(A∪B)=P(A)+P(B).