Solution
Four Speakers, Four Cities
Show the problem again
Four people (Ines, Jo, Kai and Lev) each have a different job (chef, pilot, nurse, judge), live in a different city (Oslo, Rome, Lima, Cairo), and give a talk on a different day of the week (Monday, Tuesday, Wednesday, Thursday), one talk per day. You are told: 1. Whoever lives in Rome speaks on Monday. 2. The chef speaks earlier in the week than the pilot. 3. Neither Jo nor Kai is the nurse. 4. The nurse lives in neither Rome nor Oslo. 5. The judge lives in Lima. 6. Lev speaks earlier in the week than Kai. 7. Neither Jo nor Kai lives in Lima. 8. The Cairo resident speaks on neither Tuesday nor Wednesday. In which city does the pilot live?
Worked solution
The judge lives in Lima (clue 5), and neither Jo nor Kai lives in Lima (clue 7), so the judge is Ines or Lev. The nurse is also Ines or Lev (clue 3). Hence Ines and Lev are the judge and the nurse in some order, and Jo and Kai are the chef and the pilot. The nurse does not live in Lima (the judge does), Rome or Oslo, so the nurse lives in Cairo. By clue 8 the Cairo resident speaks Monday or Thursday, and Monday belongs to the Rome resident (clue 1), so the nurse speaks Thursday. The chef and pilot live in Rome and Oslo. The Rome resident speaks Monday, and if that were the pilot, the chef could not speak earlier (clue 2); so the chef lives in Rome and speaks Monday, and the pilot lives in Oslo. (The remaining clues settle the names: Kai cannot be the chef, since Lev must speak before Kai, so Kai is the pilot and Jo the chef; Lev is then the judge, Ines the nurse.) The pilot lives in Oslo.
Source: Original puzzle written for AxiomIQ in the style of standard logic-grid puzzles.