conversations.from: human
conversations.value: Break down this math problem: It takes Derek 9 minutes to walk a mile if he doesn't have to walk with his brother. If he has to take his brother it takes 12 minutes to walk a mile. How many minutes longer would it take him to walk 20 miles if he had to take his brother?
conversations.from: assistant
conversations.value: Alone it would take him 9*20=180 minutes
  With his brother, it would take him 12*20=240 minutes
  240-180=60 more minutes