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

[Sharingaroomtinightthen]

When I posted late last night I thought I’d get maybe half a dozen replies confirming the question didn’t have the correct answer and advising whether to tell the Civil Service recruiters. But here we are 1000 posts later.

https://www.mumsnet.com/talk/am_i_being_unreasonable/5384347-maths-test-to-think-civil-service-have-it-wrong

Parklife !

A classic

divide by common factor a+b = b

Divide by zero error

shhhh. Don't spoil the fun!

So what are the maths experts on here saying? I have not read whole thread.

125%.

125% no doubt about it

I wrote pages of nonsense as I didn’t understand what I was doing.

Well you're in good company on this thread, then.

I don’t understand what you mean…
what I was trying to say is that an online multiple choice exam won’t have the scope for you to write in an alternative answer (125% in this case)

real life doesn't always have check boxes 😀it's a philosophical point.

Unfortunately there are 2 threads, in which roughly 80 of posters have been extremely keen to demonstrate just how poor their comprehension, mathematics and understanding of percentages is 😂 But, the answer is 125%, which is not one of the answers available. Which is where this all started 😊

@poetryandwine @niadainud

I think the ‘start at 50’ comes from me. A lot of posters were saying ‘imagine at the end of the first year you have 100’ so I said ‘imagine at the end of the first year you have 50’ because you then start the sum by doubling it, ie you now start with 100. In trying to make it simpler for people to understand, I thought 100 was a nice easy number and easier to visualise.

But it went fecking wrong. Again.

Yes, it’s 125%.

I know there are no ‘numbers’ in the question, it is just easier for some people to have actual numbers.

I wanted to try and point out exactly where you went slightly wrong.

Year 3-4 reduces A by a quarter of A.
A is 200% (A is NOT 200% at this point, in your last point you said A has just had a 200% INCREASE (tripling), which was preceded by a 100% INCREASE (doubling) . This means A is now 600% of its original value, so reducing by quarter will take it to 450% of its original value)

And the question is what is the increase between the time when A is 200% of its original value and when it is 450% of its original value.

200% to 450% is a 125% INCREASE.

I asked 2 maths teachers. One said 50% and the other said 450%. I asked the 2nd one to rtfq and he cane back with 125% 🤣

My DH who has a maths degree and works in finance initially said 225. I, who is fine with day to day maths but only has a lowly C grade GCSE, said 125. DH then looked at it again and admitted I was right 😂

YABU for starting a new thread. You are just showing off now OP 😂

You are over-complicating it. You have a figure at the end year 1, year 2 and year 3. They are all different, so no point calling them all 'A'. Taking the start of year 1 as 100%, the figures are 200%, 600% and 450%. You are asked for the percentage increase from 200 to 450. 450-200 (that's 250, the difference between them) is 125% of 200.

@Supperlite sorry for being careless, but I should have said 'no point calling them all proportions of A' in my previous reply (instead of 'calling them all A').

@SerendipityJane I showed this to a mathematician friend. They are also a multilinguist, high level chess player, sportsman and much travelled (don't worry - face like a potato and likes Trump). The wording was genuinely puzzling to them, and they didn't reach a definitive conclusion yet. They immediately went to algebra. We didn't have a pen handy, and that was their first request. I think there is something about the wording, maybe lots going on at once, that makes a simple calculation seem complex.

@BrickBiscuit @DadDadDad @TeenToTwenties @RedDoorBlueHouse

Thanks all! I’ve been contemplating your replies. It has taken a few days of thinking (literally…), but I think I finally understand. I wasn’t sure how you determined the methodology to answer the question; I think I found it confusing to know how to answer it because the question refers to percentages, which sound like (from the wording) each increase (doubling then trebling) is its own little individual percentage packet, if that makes sense, but the methodology to find the answer is more like using algebra (in my head, anyway).

Another confirmation, perhaps, that I should stick to my day job! 😂

Thanks again.

That's so strange. I gave it to my 12 year old, fairly average at math, son and he got the right answer in his head. It's really not complex.

There are plenty of "subtle" tests that are not what they seem. Or that can deliverer .... interesting results.

Any "Taskmaster" fans reading ?

In the quantum theory of multiverse maybe there is a universe where the answer is 225%?

Are you American ?

It is strange. I am only of average intelligence, not advanced in maths, but 'saw' it straight away.