conversations.from: human
conversations.value: James gets 80 emails a day.  20% of those emails don't require any response.  He responds to the rest of them.  How many emails does he respond to in a 5 day work week?
conversations.from: assistant
conversations.value: He gets 80*.2=16 emails he doesn't need to respond to
  So he responds to 80-16=64 emails
  So he responds to 64*5=320 emails a week