Directions: On an Island there live three types of tribes Sachcha, Jhutha and…

In truth-teller/liar/alternator puzzles, treat each tribe's rule as a constraint: a Sachcha's statements must both be true, a Jhutha's statements must both be false, and a Lota's statements must alternate — exactly one true and one false. Since exactly one person belongs to each tribe, test candidate assignments one at a time and discard any that produce an internal contradiction.

1. Assume GOOD is a Sachcha. Then both his statements must be true, so ‘UGLY is of Sachcha tribe’ would also be true — but only one person can be Sachcha, and that person is already assumed to be GOOD. This is a contradiction, so GOOD cannot be a Sachcha.

2. Assume BAD is the Sachcha instead. Both of BAD's statements must then be true: ‘I am of Sachcha Tribe’ holds directly, and ‘GOOD is of Jhutha tribe’ fixes GOOD as the Jhutha — which leaves UGLY as the remaining tribe, Lota.

3. Check this assignment against GOOD's own statements: as a Jhutha, both must be false. ‘UGLY is of Sachcha tribe’ is false (UGLY is Lota), and ‘I am of Lota tribe’ is false (GOOD is Jhutha) — both statements come out false, exactly as a Jhutha requires.

4. Check UGLY's statements as the Lota: they must alternate, i.e. exactly one true and one false. ‘BAD is of Jhutha tribe’ is false (BAD is Sachcha), and ‘I am of Lota tribe’ is true — one true and one false, matching the Lota pattern.

No other assignment of the three tribes to GOOD, BAD and UGLY survives this same check — assuming GOOD is Lota, or assuming BAD or UGLY is Sachcha in the other combinations, always forces either two Sachchas, both of a Jhutha's statements to be true, or a Lota's two statements to agree instead of alternate. So Sachcha–BAD / Jhutha–GOOD / Lota–UGLY is the only internally consistent assignment.

GOOD therefore belongs to the Jhutha tribe.