Question

Alex, Bob and Carl go for a walk every day. If Alex doesn't wear a hat, then Bob wears

a hat. If Bob doesn't wear a hat, then Carl wears a hat. Today Bob is not wearing a hat.
Who is wearing a hat?

Answer 1

Carl and Alex are wearing hats.

Explanation:

If Bob doesn't isn't wearing a hat, then Carl is, so Carl clearly is wearing a hat.

Now let's look at Alex. If he wasn't wearing a hat, then Bob would be wearing one. (If Alex doesn't wear a hat, then Bob wears

a hat). The logical conclusion is that Alex must be wearing a hat as well.