2 Three numbers are chosen at random from the set {1,2,3,4}. a Find the probability that the three numbers can form consecutive terms of an arithmetic sequence. b Find the probability that the three numbers can form consecutive terms of a geometric sequence. 3 The coffee machine in the Pi cafe has three coffee dispensers P, Q and R. The probabilities that each malfunctions on a given day are 0.007, 0.003 and 0.001 respectively. a Find the probability that exactly one of the dispensers malfunctions on a given day. b Find the probability that at least one of the dispensers will malfunction on a given day