conversations.from: human
conversations.value: James has to refuel his plane.  It used to cost $200 to refill the tank.  He got an extra tank to double fuel capacity.  Fuel prices also went up by 20%.  How much does he pay now for fuel?
  Solve it.
conversations.from: assistant
conversations.value: The cost to fill a tank went up 200*.2=$40
  So it cost 200+40=$240 to fill the tank
  That means he now pays 240*2=$480