conversations.from: human
conversations.value: John and Jack have 30 minutes to walk to school together. It takes them 6 minutes to get to the corner where the library is. It takes them another 13 minutes to get to the fire station. How much longer do they have to get to school without being late?
  Solve it.
conversations.from: assistant
conversations.value: John and Jack arrive at the library with 30 - 6 = 24 minutes left to reach the fire station.
  They then arrive at the fire station and have 24 - 13 = 11 minutes left to get to school without being late.