conversations.from: human
conversations.value: Peter has 15 birds. 1/3 are ducks. The rest are chickens and require special feed that costs $2 per bird. How much does it cost to feed the chickens?
  Find the solution.
conversations.from: assistant
conversations.value: 2/3 of the birds are chickens because 1 -(1/3)=2/3
  He has 10 chickens because 15 x (2/3) =10
  It will cost $20 to feed them because 10 x 2=20