conversations.from: human
conversations.value: Barney washes his kitchen towels once a week. He owns eighteen towels and uses two at a time that he changes to clean towels daily. He missed one week of laundry. How many days the following week will Barney not have clean towels?
  Solve it.
conversations.from: assistant
conversations.value: Barney uses 2 clean towels every day, so he uses 2 * 7 = 14 towels a week.
  He missed one week of laundry, so he would need 2 * 14 = 28 towels for 2 weeks.
  He owns 18 towels, so he has 28 - 18 = 10 less than he needs.
  Thus, Barney will not have clean towels on 10 / 2 = 5 days.