conversations.from: human
conversations.value: Break down this math problem: Mark realizes that a lot of the friends on his friends list are people he doesn't talk to anymore.  He keeps 40% of his friends list and then contacts the rest.  Of those only 50% respond.  He removes everyone who did not respond.  If he had 100 friends how many does he have left after the removal?
conversations.from: assistant
conversations.value: He contacted 1-.4=.6 of his friends
  So he contacted 100*.6=60 people
  So he removes 60/2=30 people
  So he has 100-30=70 friends left