Question 13
A mutant octopus can have six, seven, eight or nine legs. Those with seven or nine legs always lie, while those with six or eight legs always tell the truth. The green octopus says: “I have eight legs. The blue octopus has six legs.” The blue octopus says: “I have eight legs. The green octopus has seven legs.” The red octopus says: “I have nine legs. The blue octopus has eight legs.” The yellow octopus says: “I have eight legs. None of the others has eight legs.” Which mutant octopus actually has eight legs?