conversations.from: human
conversations.value: James writes from 1 PM to 4 PM every night.  He can write 5 pages per hour.  How many weeks will it take to finish his 735-page book?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: He writes for 4-1=3 hours per day
  That means he writes 3*5=15 pages per day
  So it would take him 735/15=49 days
  That means it will take 49/7=7 weeks