conversations.from: human
conversations.value: Find the answer to the math problem: A new book sold 15 copies at the bookstore on Wednesday. On Thursday the book sold three times that many copies. On Friday the book sold one-fifth the number of copies it did on Thursday. How many copies of the book did the bookstore sell by Friday?
conversations.from: assistant
conversations.value: On Thursday 15*3=45 books were sold.
  On Friday 45/5=9 books were sold
  Adding up all three days 15+45+9=69 books were sold by Friday