2 logic puzzles about octopuses entangled in their tentacles
Recreation / / December 31, 2020
If the purple octopus is telling the truth, it must have an even number of limbs. But in that case, he cannot say that he has nine tentacles. So the purple octopus is lying. Therefore, dark blue does not have eight tentacles.
But the dark blue dweller of the deep claims that he has eight legs, that is, he is lying. So he has an odd number of limbs. Saying that the dark blue octopus has six tentacles, the green one lied. Therefore, his words that he himself has eight tentacles is also not true.
It turns out that the first statement of the striped octopus is true. So the second is also true: it does have eight tentacles. And the rest of the octopuses have an odd number.
Answer: only the striped octopus has eight tentacles.
Octopuses contradict each other, so two cases are possible: either they all lie, or only one of them speaks the truth.
Let's say all octopuses are lying. This means that each of them has seven tentacles, and a total of 28. But then it turns out that the blue octopus told the truth, and this contradicts our assumption.
If three of the underwater inhabitants cheated, and the fourth told the truth, then those who lied should have seven tentacles, 21 in total, and the honest one has either six legs or eight. Therefore, together they have either 27 tentacles, or 29. It turns out that the green octopus told the truth. Thus, he has six legs, and the rest have seven.
Answer: The green octopus has six tentacles, while the others have seven.