question: 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 $50 each.  How much money profit did he make?
answer: The cheaper cards are worth a total of 30*50=$<<30*50=1500>>1500
  So all the cards together are worth 1500+4000+1000=$<<1500+4000+1000=6500>>6500
  The cost for the cards was 1800*3=$<<1800*3=5400>>5400
  So he made a profit of 6500-5400=$<<6500-5400=1100>>1100
  #### 1100