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Which answer in this list is the correct answer to this question? (2017)

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Re: Which answer in this list is the correct answer to this question? (2017)

#21
post #18

what is the question? 5 and 6 are the only possible. But if 5 is true then 6 is false None of the above can be true only with "more than one of the above (but different than all, none or one)", but then we would not be talking about the correct answer. It is assumed than only an answer can be correct. I suppose than 6 then. Updated: you are right, 6 can't be true, is the 5

If 6 was true, then 5 would also be true, making 6 incorrect.

It has to be 5

Re: Which answer in this list is the correct answer to this question? (2017)

#22

It seems that 5 is a winner, as stated in the accepted answer. That's a pity, first I thought the goal of the question was to create an instance of Yablo's Paradox. Yablo's paradox is important because you cannot just argue that the paradox arises from an obviously incorrect definition, as people sometimes do for classical semantic paradoxes.

5 is the only answer that could be correct.

But is it an answer to the question? If the question were something completely different, "How green is interstellar space?", then we would still find 5 as the answer. But "None of the above" is a non-answer. And "What is the answer to this question?" is not well defined.

Re: Which answer in this list is the correct answer to this question? (2017)

#23
post #8
post #2

An expert system answer (Prolog, CLIPS) would be cool to see here.

Using the clpb library [0]: solution([A1,A2,A3,A4,A5,A6]) :- sat(A1 =:= A2*A3*A4*A5*A6), sat(A2 =:= ~(A3+A4+A5+A6)), sat(A3 =:= A1*A2), sat(A4 =:= A1+A2+A3), sat(A5 =:= ~(A1+A2+A3+A4)), sat(A6 =:= ~(A1+A2+A3+A4+A5)). [0] https://www.metalevel.at/prolog/puzzles

Alternatively using z3 [0]:

  (declare-const a1 Bool)
  (declare-const a2 Bool)
  (declare-const a3 Bool)
  (declare-const a4 Bool)
  (declare-const a5 Bool)
  (declare-const a6 Bool)

  (assert (= a1 (and a2 (and a3 (and a4 (and a5 a6))))))
  (assert (= a2 (not (or a3 (or a4 (or a5 a6))))))
  (assert (= a3 (and a1 a2)))
  (assert (= a4 (or a1 (or a2 a3))))
  (assert (= a5 (not (or a1 (or a2 (or a3 a4))))))
  (assert (= a6 (not (or a1 (or a2 (or a3 (or a4 a5)))))))
  (assert (or a1 (or a2 (or a3 (or a4 (or a5 a6))))))

  (check-sat)
  (get-model)
  (exit)
The model is satisfiable where only a5 is true, anyone can run it themselves and play with it [1].

Additionally forcing a5 to be false by adding the following to the list of assertions:

  (assert (not a5))
And the model becomes unsatisfiable.

Edit: Finally, to make sure there's not some possible solution where a5 is true as well as another assertion you could alternatively add this assertion:

  (assert (and a5 (or a1 (or a2 (or a3 (or a4 (or a6)))))))
And the model also becomes unsatisfiable. So 5 only seems to be the correct answer.

[0] https://github.com/Z3Prover/z3

[1] https://rise4fun.com/Z3/1DMW

Re: Which answer in this list is the correct answer to this question? (2017)

#25

Similar one I enjoyed in the Naive Bayes article from yesterday https://blog.floydhub.com/naive-bayes-for-machine-learning/ Multiple Choice: If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

The answer to that question is obviously 0% Now, what would be the answer to the same question with the answer options: A) 20% B) 40% C) 60% D) 20% E) 0%

Your answer above is incorrect in a very funny way. "At random" implies an uninformed prior, but the question presupposes there's a correct answer, as 0% is missing.

0% and 100% are indefensible for any uninformed prior.

There are two answers giving the correct probability for uniform prior. One of the 25% is a wrong answer despite being indistinguishable. Such a thing can happen because of a typo or in any myriad of ways. It's not a paradox.

If it asked the question "knowing that probability of success for random single choice question out of 4 answers is 25%, what is the probability of selecting the correct answer at random from one of the below?" That formulation implies an informed prior.

That'd have the answer of prior% with 50% for uniform prior, but it's not duplicated, so the actual answer is 0% making it a paradox. If it were duplicated, (answers only 25% and 50% available) the either answer of 50% would hold.

But that was not the question asked in yours or former question.

Re: Which answer in this list is the correct answer to this question? (2017)

#26

LinkedIn's skill tests are hilariously poor. They ask unanswerable questions, and mistype the answers. The more familiar you are with the subject matter, the more uncertain you become.

I noticed those randomly one day and did a few of them. I failed the one for the primary programming language I have worked in for the past decade and passed ones for two different languages I have hardly used and AWS, which I barely know anything about outside of EC2 and R53.

I felt like there was a big difference in the quality of the questions and answers for each quiz. For the AWS one, for example, the phrasing used for most of the questions and answers made the correct answer basically obvious without actually knowing it to be correct.

Re: Which answer in this list is the correct answer to this question? (2017)

#27
I've always thought of these as "Wayside School" problems, because I first encountered them in the children's book, Sideways Arithmetic From Wayside School by Louis Sachar. I highly recommend it for any child who is into puzzles. I really enjoyed how the book deconstructed the format of tests and quizzes that I was so familiar with at the time. My favorite section was the sideways math, where words are added or multiplied and you had to deduce the values of the letters. E.g.,

      D O G
    x   A D
    _______
    
      D O G
    A D O
    _______
    
    A G O G
Maybe children don't learn to do arithmetic like this anymore and this section will be utterly impenetrable to them.

Re: Which answer in this list is the correct answer to this question? (2017)

#29

Earlier quoted context omitted.

The answer to that question is obviously 0% Now, what would be the answer to the same question with the answer options: A) 20% B) 40% C) 60% D) 20% E) 0%

Your answer above is incorrect in a very funny way. "At random" implies an uninformed prior, but the question presupposes there's a correct answer, as 0% is missing. 0% and 100% are indefensible for any uninformed prior. There are two answers giving the correct probability for uniform prior. One of the 25% is a wrong answer despite being indistinguishable. Such a thing can happen because of a typo or in any myriad of…

>0% and 100% are indefensible for any uninformed prior.

If none of the answers are correct, the chance of picking the correct answer is 0%.

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