conversations.from: human
conversations.value: Jane had a 500 page book to read. The first half of the book Jane read with a speed of 10 pages per day, and the second half with a speed of 5 pages a day. How many days did Jane spend reading this book?
  How to solve this?
conversations.from: assistant
conversations.value: Half of the book means 500 / 2 = 250 pages.
  Reading the first half took Jane 250 / 10 = 25 days.
  Reading the second half of the book took Jane 250 / 5 = 50 days.
  So in total Jane needed 25 + 50 = 75 days to read the whole book.