conversations.from: human
conversations.value: John buys a gaming PC for $1200.  He decides to replace the video card in it. He sells the old card for $300 and buys a new one for $500.  How much money did he spend on his computer, counting the savings from selling the old card?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: He spent an extra 500-300=$200 on the video card
  That means the total cost was 1200+200=$1400