Puzzle of the Week 3

We consider two of FAECTOR's committees: the very trustworthy Estimator, of which the members always tell the truth, and the very untrustworthy IntAct Committee, of which the members always lie. You meet three FAECTOR members, but you don't know from which of these two committees they are. Therefore, you ask the first person if the two others are from the same committee and that person indicates that is indeed the case. You ask the second person the same question, and the answer is again the same. Will the third person also say the others are members from the same committee? 

Solution of the previous puzzle: No one shook 9 or 10 hands (you know yourself and your fellow committee member), meaning the number of hands shaken varies from 0 till 8. Consider the person who shook 8 hands: he can't have shaken hands with the person who shook 0 hands, meaning that person is in his committee. In the same way that 8 and 0 go together, 7 and 1 go together, 6 and 2 and 5 and 3. This means 4 is left, so Nynke shook 4 hands!

About this article

Written by:
  • Tobias Hoogteijling
| Published on: Dec 28, 2015