conversations.from: human
conversations.value: John buys 30 ducks for $10 each.  They weigh 4 pounds and he sells them for $5 per pound.  How much profit did he make?
  Find the solution.
conversations.from: assistant
conversations.value: He bought the ducks for 30*10=$300
  He sold each duck for 4*5=$20
  So he sold all the ducks for 30*20=$600
  So he made a profit of 600-300=$300