Advisors for students in the Services office, receive an average of 220 non-spam emails every 8 hour working day. The advisors estimate that of these, approximately 150 need a reply by the end of the day. Over a period of time, the advisors find that the average number of unanswered emails in their inboxes that still need a reply is 5.

a) On average, how much time (in minutes) does it take for an advisor, at the Services office, to send a reply to an email that needs a response?

b) The Services office estimates that it takes an advisor on average 7 minutes to read an email that does not need to be replied. On average, how many non-spam emails that do not need a response are in the inboxes of the advisors waiting to be read?

c) On average, 60% of the incoming emails that require a reply are from students enrolled in one or more classes, this semester. The average time for an advisor to respond to these emails from students enrolled in classes is 10 minutes. How much time on average (in minutes) does it take an advisor to respond to the remaining emails, from students not enrolled in classes this semester, that still need a reply?