Maths question - Civil Service is wrong (we now have 100% more threads about the subject)

I am firmly in the 125% camp, however I think I have just spotted a flaw:

The question says, "In one year the circulation of News Today doubled." But this year can't be "the first year" of circulation, otherwise you're doubling zero.

So it can be the first year that we're looking at, but not the first year of circulation. So when we're asked to compare the end of the first year with the end of the third year, it's not truly the first year.

However, doubling, tripling or reducing zero by a quarter all give you zero, so I'm sure that's not what the question-setter intended.

Hope that makes sense.

The Monty Hall problem is a beautiful example of how probabilities can be counterintuitive.

This is an example of a poorly worded question - poorly worded because, while the question is unambiguous, the correct answer is not provided so we can't be sure that the setter understood the words they were using, like so many on this thread.

Not remotely the same thing.

For some reason I am reminded of a wonderful phrase from "Avenue 5", uttered by the impossibly perfect Hugh Laurie ...

"We've just seen 7 people stupid themselves to death".

Afraid your dad is wrong! Feel free to show him my earlier explanation and challenge him to find an error in it…

@Samscaff 125 is what I originally thought. Then I had 225. My dad, who is much more expert in such a field, agrees with @SerendipityJane and says 450 😂 which is at least one of the answers on there

so… I shall eagerly await if OP gets a response!

And as @SoSoLong says below, even when explained, some purportedly skilled mathematicians have doggedly maintained it's ambiguous or one of the incorrect answers. I find that incomprehensible.

Oh I see. Yes, I guess you're right. I think there are a few reasons why people are getting the wrong answer.

🤔.

The insisting they are right might be due to neurodiversity. As someone with a lot of experience in that field I recognise that particular stubbornness and even the phrasing of it.

The problem is mathematically very simple. It's also easy to spout out the wrong answer if you've not read the question properly (ie it's increase from the end of y1, not from the start, and it's percentage increase, not percentage). A lot of people who skim read the question will get it wrong through carelessness, not lack of knowledge.

But the sheer number of people on this thread who were made aware of their mistake and still insisted they are right is ridiculous.

Yes, you have.

End Y1 - this is the start point. Call it N (for Number).
End Y2 - 3N
End Y3 - 2.25N. This is the end point.

The increase in the end no. minus the start no., i.e. 2.25N minus N. The increase is therefore 1.25N.

The percentage increase is Increase / start no. * 100.
1.25N / N *100. This comes to 125%.

It's very confusing and I think a silly way to express things. I always have to remind myself that a 100% increasing is doubling and work from there. I feel like once a week I find myself complaining to be husband: why doesn't the news article just say it "more than 8 times bigger" rather than " 707% bigger" or whatever silly % it is. I think very few people understand the latter.

I'd be really interested to see whether more people get it right without the multiple choice element.

One PP suggested they tweaked the question and forgot to check it still matched one of the answers

Given the obscene amount being spunked and planned on "AI" then that is unforgiveable and pretty much a resigning offence for whoever manages the civil service then. If there is no one in the civil service capable of running their entrance exam through a basic sanity check then the UK is doomed. (See also candidates who can't find "F7" ...)

Yes, Hanlon would explain the missing answer button being a mistake. One PP suggested they tweaked the question and forgot to check it still matched one of the answers. However, what explains the apparent difficulty, for some, in getting the correct answer?

Without the full guidance, it's hard to go beyond what seems to be a flawed test.

As I noted, when I had to take a serious screening test, the guidance explicitly said that you would not be able to answer all the questions. As I was told when I attended the follow up (for people who passed) that wasn't a challenge to try and psych the candidates out. It was a statement of fact they they were expected to verify and then address.

And it was the addressing they were testing. Not the maths.

Bottom line is if you towards the end of an MSc (or higher) in a technical subject, and you find a potential employer is testing your "maths" skills, then maybe - just maybe - you've missed the point.

Now whether or not that is the case here, we don't know. In the absence of further data, Hanlon reigns supreme.

[Sorry for re-posting this. I forgot to “quote” your post to which I was replying]

No. Was there any in this case, according to the OP? I did see your (was it yours?) example of a test where those who didn’t listen failed by not hearing they didn’t have to answer everything. And I appreciate your posts about it perhaps being a bit more than just “Do this sum”.

That wasn’t my point. I agree it is simple arithmetic + straightforward reasoning. I did that myself off the bat, got the solution and realised the MCQ was mistaken. But several ‘experts’ on the threads got it wrong. My friend also had trouble seeing through it. Yes, it’s simple. But the presentation has something that foxes people it shouldn’t. I’m interested in why that is.

No. Was there any in this case, according to the OP? I did see your (was it yours?) example of a test where those who didn’t listen failed by not hearing they didn’t have to answer everything. And I appreciate your posts about it perhaps being a bit more than just “Do this sum”.

"They" sound a bit full of themselves. You don't need to be a mathematician, to have circumnavigated the globe, to speak Mandarin and Icelandic, to have competed in the Olympics or to be a chess grandmaster to answer this simple question.

It's just some arithmetic mixed in with some pretty straightforward verbal reasoning.

Did they also ask for the candidate guidance ?

Yes, I showed them the photo in the OP. They didn’t reach a conclusion, but gave a couple of answers at first sight and looked for a pen. I think writing the algebra down would have solved it. Perhaps they couldn’t see the wood for the trees (and we had had a couple of beers already). Though I got it at first sight, in my head, and I’m thick.

Did they have sight of the multiple choice answers like the people on the original thread. Maybe it's more to do with faith in authority than the wording of the question itself?

On second thoughts I make it 225% now, have I lost my mind? 😂 this thread is gold

It is indeed a trivial calculation. Another trivial calculation is to add up the number of professed experts on the threads who get it wrong. There must be a reason for this. My guess is that the wording is counterintuitive. What’s yours?