conversations.from: human
conversations.value: Find the answer to this math problem: A sack of rice, which is 50 kilograms,  costs $50. If David sells it for $1.20 per kilogram, how much will be his profit?
conversations.from: assistant
conversations.value: David's revenue for the 50 kilograms of rice is $1.20 x 50 = $60.
  So, his profit is $60 - $50 = $10.