Bunuel
In a magical swamp there are two species of talking amphibians: toads, whose statements are always true, and frogs, whose statements are always false. Four amphibians, Brian, Chris, LeRoy, and Mike live together in this swamp, and they make the following statements.
Brian: "Mike and I are different species."
Chris: "LeRoy is a frog."
LeRoy: "Chris is a frog."
Mike: "Of the four of us, at least two are toads."
How many of these amphibians are frogs?
(A) 0
(B) 1
(C) 2
(D) 3
(E) 4
Let's look at Chris and Leroy. If they are both toads, then they are both lying, which they can't do if they are toads. If they are both frogs, then each of their statements is true, which they can't do if they are frogs. That means one is a frog and the other is a toad. We have either Ct/Lf or Cf/Lt.
If Brian is a toad, then Mike is a frog. If Mike is a frog, there is at most one toad. But we already have one toad in Brian and a second toad in either Chris or Leroy. Thus, Brian can't be a toad. Bf. If Bf, then Brian's statement tells us Mf.
Bf
Mf
Either Cf or Lf but not both
Three frogs.
Answer choice D.