A vending machine dispenses hot chocolate or coffee. Service duration is 30 seconds per cup and is constant. Customers arrive at a mean rate of 80 per hour (assume Poisson). Also assume that each customer buys only one cup. a. Determine the average number of customers waiting in line. (Round the final answer to 3 decimal places.) Average number of customers b. Determine the average time customers spend in the system. (Round the final answer to 1 decimal place.) Average time minute c. Determine the average number of customers in the system. (Round the final answer to 2 decimal places.) Average number of customers = ?