conversations.from: human
conversations.value: Carlson bought land that cost $8000 and additional land that cost $4000. He initially owned 300 square meters of land. If the land he bought costs $20 per square meter, how big is his land after buying the new land?
  How to solve this?
conversations.from: assistant
conversations.value: Carlson bought land that cost $20 per square meter, therefore the size of the land he bought is 8000/20 = 400.
  And the size of the other land he bought is 4000/20 = 200.
  Therefore the total size of the land he owns is 400+200+300 = 900.