problem-set/puzzles/truth_lies/tandl27.desc Created : 09/03/86 Revised : 07/18/88 Natural Language Description: Truthtellers and Liars Puzzle #27 There is an island with exactly two types of people--truthtellers who always tell the truth and liars who always lie. There are a group of three people, A, B, and C on the island. A stranger passes by and asks A, "How many truthtellers are among you ?" A answers indistinctly. So the stranger asks B, "what did A say?". B replies "A said that there is exactly one truthteller among us." Then C says, "Don't believe B; he is lying!" What are B and C. Versions: tandl27.ver1 : Declarative representation, using hyper-resolution. answer: B is a liar and C is a truth-teller. created by : Swaminathan and Pillai verified for ITP : 09/03/86 translated for OTTER by : K.R. verified for OTTER : 07/18/88