The number of suits sold per day at a retail store is shown in the table below, with the corresponding probabilities. Find the mean of the distribution. If the manager of the retail store wants to be sure that he has enough suits for the next 5 days, how many should the manager purchase? Number of suits sold X 19 20 21 22 23 Probability P(X) 0.2 0.2 0.3 0.2 0.1