1. Lucille has a large collection of classic books on four shelves in her office. The first shelf makes up 25% of the total and holds books written in the
nineteenth century by Dickens, Hugo, and Bronte. The second shelf makes
up one-eighth of the total number of books and holds Shakespeare's plays.
The third shelf makes up two-fifths of the total and holds twentieth-century
books by Steinbeck, Fitzgerald, and Hemingway. The fourth shelf holds 27
books, including mysteries by Hammett, Chandler, Christie, and Conan
Doyle and science fiction by Asimov, Clarke, and Heinlein. How many
books are on the third shelf?[25]