There was trouble from the Grundi. One of them damaged the spaceship by hurling a rock at it. The astronauts couldnít figure out what the Grundi had to gain by their hostile act. Was it just vandalism, done out of sheer spite? Or perhaps not everyone on Mars was happy to see the Earthlings return. The Martian Police Chief brought in five Grundi for questioning. Like all Grundi, they sometimes told the truth and sometimes lied. The suspects each made three statements, two of which were true and one of which was false. And the guilty rock-hurler was revealed by the Police Chief.
Zum said: (a) I am innocent. (b) Tset did it. (c) I have never used a rock to destroy anything.
Uk said: (a) I did not do the damage. (b) Yan is not my friend. (c) The Earthmanís vehicle is on Grundi space.
Pala said: (a) I am innocent. (b) Tset is guilty. (c) I never saw Yan before.
Tset said: (a) I did not throw the rock. (b) Yan did it. (c) Zum did not tell the truth when he said I did it.
Yan said: (a) I am innocent. (b) Uk is guilty. (c) Pala and I are old friends.
Who was the culprit? Justify by trying to arrange your reasoning in an understandable fashion (e.g. think "proof").
Multiple approaches can be taken. A chart of all possible cases could be set up....or some prefer to focus on one person and test assupmtions about their relative truthfulness.
The Police Cheif was able to do it...so you can to!