50. A new shopping mall is considering setting up an information desk manned by one employee. Based upon information obtained from similar information desks, it is believed that customers will arrive at the desk at the rate of 15 per hour. It takes an average of two minutes to answer a question. It is assumed that arrivals are Poisson and answer times are exponentially distributed. What is the expected time (in hours) a person spends waiting in line to have his question answered?

Select one:

a. 0.0100 hours

b. 0.0425 hours

c. 0.0333 hours

d. 0.6000 hours

e. 0.3333 hours