conversations.from: human
conversations.value: William is a jockey. He can ride his horse for 6 hours a day. Over 6 days, he only used the maximum riding time twice.  On two days he rode his horse for only 1.5 hours a day and half the maximum time for the next two days. How many hours did William ride his horse during those 6 days?
  Solve it.
conversations.from: assistant
conversations.value: William used two days to the limit, which means 6 * 2 = 12 hours of horse riding.
  For two days he rode a horse 1.5 a day, which makes up to 1.5 * 2 = 3 hours.
  For the next two days, he used only half of the maximum time which means 6 * 0.5 = 3 hours a day.
  That means 2 * 3 = 6 hours during these two days.
  So in total William rode his horse for 12 + 3 + 6 = 21 hours.