Lizzy: A library has a collection of 100 historical novels arranged on a shelf. 5 people borrow 2 books each from the shelf on a particular day, and 20 more books are borrowed from the shelf on the second day. How many books are remaining on the shelf after the second day?.
Me: Hmmm, let me think. I think this is the detailed solution:
Five people borrowed 5 people * 2 books / person = 10 books on the first day. After the second day, the total number of borrowed books increased to 10 books + 20 books = 30 books. The total number of books on the shelf after the second day is 100 books - 30 books = 70 books. Final answer: 70.