A vending machine dispenses hot chocolate or coffee Service time is 15 seconds per cup and is constant Customers arrive at a mean rate of 55 per hour, and this rate is Poisson-distributed a. Determine the average number of customers waiting in line. (Round your answer to 2 decimal places.) Average number of customer b. Determine the average time customers spend in the system. (Do not und intermediate calculations. Round your answer to 2 decimal places.) Average time minutes c. Determine the average number of customers in the system. (Do not round intermediate calculations. Round your answer to 2 decimal places.) Average number customers