conversations.from: human
conversations.value: Break down this math problem: There are 40 more buyers in the grocery store today than yesterday. There were half the number of buyers yesterday as there were the day before, and the day before had 50 buyers. Nobody visited the store on more than one day. What's the total number of buyers who've visited the store in the three days?
conversations.from: assistant
conversations.value: If yesterday the number of buyers was half the number of buyers the day before, then yesterday there were 1/2*50 = 25 buyers.
  Today has 40 more buyers than yesterday, so there were 40+25 = 65 buyers today.
  The total number of buyers in the store for the three days will be 65+25+50 = 140 buyers