PROBLEM 2: Consider a grocery store between the hours of 5 RM. and 3 PM. on a weeknight. Suppose three checkout lanes are typically open, each checkout can handle customers with any number of items, and each checkout has a dedicated bagger. The maximum number of people in a line is 10. It has been observed that checking out [including bagging] takes a mean of 3 minutes per customer and that this is approximately normally distributed with a standard deviation of {3.5 minutes. The mean amount of time between customer arrivals at the checkouts is 1 minute and can be approximated by an exponential distribution. Assume it is equally likely that a customer will enter one of the three lines. The store uses the following model: H i:i\\. (t3' |:|' Wk :1 Determine the overall mean checkout {waiting and service]: time