conversations.from: human
conversations.value: John decides to replace all his VHS with DVDs.  He can trade in his VHS for $2 each and then buy the DVDs for $10 each.  If he has 100 movies, how much does it cost to replace his movies?
  Solve it.
conversations.from: assistant
conversations.value: It cost 10-2=$8 to replace each movie
  So it would cost 8*100=$800 to replace everything