conversations.from: human
conversations.value: Police officer A patrols 36 streets in 4 hours. His colleague, officer B, patrols 55 streets in 5 hours. How many streets will both officers patrol in one hour?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: Officer A patrols 36 streets / 4 hours = 9 streets/hour.
  Officer B patrols 55 streets / 5 hours = 11 streets/hour
  Together officer A and B patrol 9 streets/hour + 11 streets/hour = 20 streets/hour.