Hexus IQ - A Problem Almost Everyone Gets Wrong (and an extra one for Maths guys)

[Galant]

Completely stolen from the Guardian and James Grime.

I'll post a poll - please answer there - your anonymity will be preserved.

PLEASE DO NOT POST THE ANSWER OR A HINT AT THE ANSWER OR THE LOGIC INVOLVED UNTIL THE POLL HAS EXPIRED.

Please also don't answer if the problem isn't brand new to you.

As usual, the honour system applies. The poll is anonymous so there are no cookies to be earned by cheating and Googling it.

Here's the problem:

Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?

A: Yes
B: No
C: Cannot be determined

Please answer on the poll.

The answer will be given when the poll expires.







Extra Problem (A maths question but related to the main problem via the logic involved):

Can an irrational number to the power of an irrational number produce a rational number - Yes or No?

SPOILER - Here's a link to the video by James Grime who gives the second problem as well as solutions to both problems. DO NOT WATCH THE VIDEO IF YOU DON'T WANT THE ANSWERS. Same applies for this link to the original Guardian article.


Once again - PLEASE DO NOT POST THE ANSWER OR A HINT AT THE ANSWER OR THE LOGIC INVOLVED UNTIL THE POLL HAS EXPIRED.

Sorry for the all caps but didn't want anyone to miss the line on a TLDR.

[virtuo]

Well I've picked what I think is the obvious one based on the data available - question is not concrete enough for my liking!

[Spreadie]

Answered the first one (all the information you need is there), but no idea on the second question.

[TeePee]

Great question! I can see why people have difficulty.

[TheAnimus]

This is a terrible question, it relies on the odd wording of it. I've got the right answer I assume, but only because I've had years of experience working with terrible BAs who describe things in the most infuriating manner possible.

[Gerrard]

It would be much more difficult to follow if it was given verbally.

I personally prefer the three prisoners in hats logic question.

[hb904460]

The wording is fine.

[Saracen]

I can't see any problem with the wording either.

[Peter Parker]

I was confused at first because I just read the poll at the top, not the actual post. Perhaps I failed the intelligence test for a few minutes then.

Regarding the irrational/rational ... my instinct is yes. I assume we can discuss the bonus question because it doesn't affect the poll?

Edit - just watched the video for the second question. An elegant proof of the answer, which reminds me of the classic proof that sqrt(2) is irrational. It's a 50/50 chance

[virtuo]

Had another think about it this morning, know I've got the wrong answer now - just needed to go a step further than I had originally.

I guess the wording is fine if you know it's designed to be a puzzle.

Pass the dunce cap.

[malfunction]

Well the wording and choices given for the 1st problem - and the fact that it's a trivial question - leads you to the wrong answer (guilty as charged) unless you bother to write it out but the more complex / abstract nature of the 2nd problem and the reduction in the possible answers means you spend more time thinking about it which actually makes it 'easier' to get right (stops you from leaping to conclusions without giving the problem more thought). So rather than (just) focussing on part of the question you end up thinking "Can a square root of a rational number be an irrational number?".

[TheAnimus]

I can't see any problem with the wording either.

The results show it's not!

Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?

So let's try and make this clearer:

Jack who is married is looking at Anne, Anne is looking at George who is unmarried. Is there a married person looking at an unmarried person?

We could probably reword it and make it even more clear.

In the following scenario, is there a married person looking at someone who is unmarried?

Jack who is married is looking at Anne, Anne is either married or unmarried, Anne is looking at George who is unmarried.

Now we've enumerated the possible values, by putting our predicate against each entity.

But then I come from a background of computer science where we try and explain things are clearly, and unambiguously as possible. Obviously the real answer is that Anne is in a civil partnership. Now a civil partnership is often fungible with a marriage in many circumstances, but often not, so we can break the whole thing with just a little bit of real world creativity. Much like storing gender in a boolean.

[malfunction]

Obviously the real answer is that Anne is in a civil partnership.

+1

[TheAnimus]

Marriage is a good example for teaching people data analysis. A civil partnership sometimes offers the same legal facilities as a 'real' marriage, sometimes it's directly interchangeable. But then you have the whole but meh jesus gang who denounce it as never the same. Things can be directly interchangeable for some purposes, but not others. For the computer science students out there you can use this as a good example for prototypal inheritance vs classical object oriented.

[virtuo]

The question doesn't explicitly state that those 3 people are the ONLY 3 people, and it asks

Is a married person looking at an unmarried person?

On Earth? Probably. But it cannot be determined. I'm fairly certain my married boss is watching me (unmarried) waste time on here. Is there a happily married sniper hidden in the building across the road, sights firmly fixed on George? Maybe, probably. But that can't be determined.

Is Jack a vicar, Is Anne a bigamist and George oblivious that his impending marriage is a sham? Maybe they've exchanged rings but not signed the paperwork yet.

Have Jack's divorce papers been signed and approved half way through me reading the question? They should be if he's watching Anne ogling George.

Did Anne blink at the moment I posted my answer? Maybe.


Need more input, and this dunce cap is very tight.

[scaryjim]

... Much like storing gender in a boolean.

This is absolutely fine in English-speaking countries, as English is a non-gendered language so gender is always false in English