Penguin Modern Classics

Penguin Modern Classics names 55 books, every one listed here. The most approachable of them is Of Mice and Men by John Steinbeck (difficulty 34/100, about 1.7 hours); the hardest is The Sound and the Fury by William Faulkner (80/100).

Questions

How many books are on Penguin Modern Classics?
55, all of them listed here with how hard each is to read and how long it takes.
Which book on Penguin Modern Classics is the easiest to read?
Of Mice and Men by John Steinbeck, difficulty 34/100, about 1.7 hours. The hardest is The Sound and the Fury by William Faulkner, at 80/100.
How long would it take to read every book on Penguin Modern Classics?
About 438 hours for the 55 books ReadingRate measures, at 250 words a minute adjusted for each book's difficulty: 219 days at two hours a day.

Other lists: Penguin Classics Collection, NYRB Classics, Everyman's Library, Library of America, Biblioteca Ayacucho, Bibliothèque de la Pléiade, Heinemann African Writers Series, Oxford World's Classics, UNESCO Collection of Representative Works. All lists.