Question 7 Plz!

... Selurus. Question Completion Status: QUESTION 7 A single Automated Teller Machine (ATM) is located on the ground floor of a popular shopping mall. Service time at this machine is exponentially distributed. On average, the ATM machine can serve a customer in 3 minutes. Customer arrivals at the machine are Poisson distributed, with an average of 15 customers an hour. Relevant formulas to analyze this M/M/1 model are available in your textbook What is the probability that this machine is being used? a. 10% b. 70% c. 30% d. 50% e. 90% QUESTION 8 It takes a total of 400 seconds for one technician to assemble one AirRules smart phone, working alone. However, AirRules manufactures its smart phones with twenty technicians staffing a twenty station assembly line, producing one smart phone every 30 seconds. How efficient is the AirRules smart phone assembly line? 33% O 67% 79% - 50%