conversations.from: human
conversations.value: Can you walk me through the solution of: A tomato vendor decides to switch who he buys his tomatoes for.  He sells 500 tomatoes a day.  He used to buy them for $.5 each but he gets a new vendor who sells them for $.4 each.  How much money does he save a week?
conversations.from: assistant
conversations.value: He buys 500*7=3500
  He used to pay 3500*.5=$1750
  He now pays 3500*.4=$1400
  So he saves 1750-1400=$350