A classic book with a bunch of random problems in elementary probability (but not statistics). They are not very difficult, ranging from easy to moderate in difficulty. Some of them touch on significant ideas (like random walks, coupon collector problem, German tank problem), but the majority are quite arbitrary (maybe suitable for a contest problem).
The solutions are fairly readable. The problem is that too much attention is given to solving the particular problem, and not enough on generalizing the principles, even when the problem has deep connections. I only gave the book a quick skim because I don’t expect to learn that much from it.