The time taken to solve a standard Sudoku puzzle follows a normal distribution with a mean of 7.3 minutes and a standard deviation of 0.8 minutes. (a) What is the probability that a randomly chosen person could solve this Sudoku puzzle in less than 8 minutes? (b) What is the probability of participants who could solve this puzzle in between 7 and 8.5 minutes? 2. The number of telephone calls made to a switchboard during an afternoon can be modelled by a Poisson distribution with a mean of eight calls per five-minute period. Find the probability that in the next five minutes if i. no calls are made. ii. at least three calls are made.