A department store manager wishes to investigate whether the method of payment chosen by customers is related to the size of their purchases. The manager has cross-classified a sample of 250 customer purchases, as shown in the following table. One of these 250 customers is selected at random. Method of payment Size of Purchase Cash (C) Credit Card (C2) Under RM20 (U) 51 31 RM20 or more (M) 65 103 (a) What is the probability that the selected customer made a purchase of under RM20 or make payment by cash? (2 marks) (b) What is the probability that the selected customer paid by cash given that he has purchased of more than RM20? I (2 marks) (c) Are the events "payment by cash" and "purchase of under RM20" mutually exclusive events? Explain. (2 marks)