conversations.from: human
conversations.value: Can you walk me through the solution of: Mark decides to buy packs of old magic cards and open them to sell.  He buys 3 packs for $1800 each.  He gets 1 card that is worth $4000 and another card worth $1000.  There are 30 more cards worth an average of $50 each.  How much money profit did he make?
conversations.from: assistant
conversations.value: The cheaper cards are worth a total of 30*50=$1500
  So all the cards together are worth 1500+4000+1000=$6500
  The cost for the cards was 1800*3=$5400
  So he made a profit of 6500-5400=$1100