This is a fun logic puzzle from one of Ian Stewart’s many math collections. I discovered that the problem actually is basically one of Lewis Carroll’s examples from an 1896 book:
- The only animals in this house are cats.
- Every animal that loves to gaze at the moon is suitable for a pet.
- When I detest an animal, I avoid it.
- No animals are meat-eaters, unless they prowl by night.
- No cat fails to kill mice.
- No Animals ever take to me, except those in this house.
- Kangaroos are not suitable for pets.
- Only meat-eaters kill mice.
- I detest animals that do not take to me.
- Animals that prowl at night love to gaze at the moon.
If all these statements are correct, do I avoid kangaroos, or not?