conversations.from: human
conversations.value: Charlie is a tennis pro.  He spends most of the day teaching others lessons on how to improve their game.  His standard fee is $80 per hour for lessons, but he reduces his rate by 25% when he is giving lessons to a veteran.   If today Charlie has 4 1-hour lessons at his standard rate and 2 1-hour lessons with a veteran, what is the total amount of money he will make for the day, in dollars?
  Solve this problem.
conversations.from: assistant
conversations.value: 4 1-hour lessons at his standard rate cost 4*$80=$320.
  Reducing the rate by 25% for veterans means he takes $80/4=$20 off his standard fee.
  Thus, for veterans, he charges the reduced rate of $80-$20=$60 per hour,
  Thus, 2 1-hour lessons with veterans cost 2*$60=$120.
  All together, Charlie will make $320+$120=$440 for the day.