D is incorrect

Problem 7-15 (Algo) Students arrive at the Administrative Services Office at an average of one every 24 minutes, and their requests take, on average, 16 minutes to be processed. The service counter is staffed by only one clerk, Judy Gumshoes, who works eight hours per day. Assume Poisson arrivals and exponential service times. a. What percentage of time is Judy idle? (Round your answer to 1 decimal place.) Answer is complete and correct. Percentage of time 33.3 b. How much time, on average, does a student spend waiting in line?(Do not round intermediate calculations. Round your answer to 1 decimal place.) Answer is complete and correct. Average time 32.0 minutes points c. How long is the (waiting line on average? (Round your answer to 2 decimal places.) Answer is complete and correct. Average length of the waiting line 1.33 customers d. What is the probability that an arriving student (just before entering the Administrative Services Office) will find at least one other student walting in line? (Do not round intermediate calculations. Round your answer to 2 decimal places.) Answer is complete but not entirely correct. Probability 66.67