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Original poster

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

434 replies

Sharingaroomtinightthen · 02/08/2025 13:36

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

Maths question - Civil Service is wrong (we now have 100% more threads about the subject)
OP posts:
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7
poetryandwine · 13/08/2025 12:42

miraxxx · 13/08/2025 12:14

Trump has unveiled a number of moves aimed at cutting drug prices in recent months, but he has yet to move the needle on reducing costs – much less slashing them by 1,500%, which is mathematically impossible, experts say.

I would like the experts to expand on this. Yes you can slash prices by 1500%. It simply means that the new price is 1/16 of the original price - whether it is practically possible is one thing, whether is it is mathematically possible is another. A drug which used to cost $16 becomes $1. The only mathematical limit is that you do not want to go into negative numbers which effectively means you paying people to "buy" the drug. Trump should be held accountable for his incredible claims, so should the experts.

This isn’t how percentages work. The whole at the beginning is 100%. You cannot decrease the initial amount by more than 100%.

OTOT you can increase the initial whole by many multiples of itself, so you could increase by 1500%.

Since you asked about credentials, I am a STEM PhD and academic.

miraxxx · 13/08/2025 12:14

Trump has unveiled a number of moves aimed at cutting drug prices in recent months, but he has yet to move the needle on reducing costs – much less slashing them by 1,500%, which is mathematically impossible, experts say.

I would like the experts to expand on this. Yes you can slash prices by 1500%. It simply means that the new price is 1/16 of the original price - whether it is practically possible is one thing, whether is it is mathematically possible is another. A drug which used to cost $16 becomes $1. The only mathematical limit is that you do not want to go into negative numbers which effectively means you paying people to "buy" the drug. Trump should be held accountable for his incredible claims, so should the experts.

Merryoldgoat · 12/08/2025 17:16

@cakeorwine

This really is the thread that keeps giving 🤣

SerendipityJane · 10/08/2025 09:41

BrickBiscuit · 09/08/2025 22:17

Wot's everybody talking about? KBs? pelcgb?

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I know one word that will automatically get a post banned. It can make talking about old church architecture very difficult if you can't think of a synonym. It's origins are from the ancient Greek word for "hidden".

"KBs" is kilobytes.

SerendipityJane · 10/08/2025 09:38

cakeorwine · 09/08/2025 21:52

I don't even know if MNHQ are even going to look at the link!

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I think you may have to nudge them. I've had that in the past. They block first, ask questions never.

BrickBiscuit · 09/08/2025 22:17

cakeorwine · 09/08/2025 21:52

I don't even know if MNHQ are even going to look at the link!

Show quote history

Wot's everybody talking about? KBs? pelcgb?

cakeorwine · 09/08/2025 21:52

BrickBiscuit · 09/08/2025 21:49

I see cakey’s subsequent explanation and get that it’s 0.2c per KB. But what on earth is the pelcbg word? Intriguing.

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I don't even know if MNHQ are even going to look at the link!

BrickBiscuit · 09/08/2025 21:49

SerendipityJane · 09/08/2025 14:30

Ooooohhhh !!!! Some intrigue !

I wonder what on earth @cakeorwine could have posted on this thread to cause MNHQ to feel for the pearls ?

I wonder if it's the pelcgb word ?

I see cakey’s subsequent explanation and get that it’s 0.2c per KB. But what on earth is the pelcbg word? Intriguing.

cakeorwine · 09/08/2025 16:13

SerendipityJane · 09/08/2025 14:30

Ooooohhhh !!!! Some intrigue !

I wonder what on earth @cakeorwine could have posted on this thread to cause MNHQ to feel for the pearls ?

I wonder if it's the pelcgb word ?

Nothing too exciting. It's about someone trying to explain to a company that $0.002 per KB is not the same as 0.002 cents per KB.

And that if you multiply 0.002 cents * 35893 KB, you don't get $71.786

The person on the phone was struggling with the idea of 0.002 cents.

SerendipityJane · 09/08/2025 14:30

Ooooohhhh !!!! Some intrigue !

I wonder what on earth @cakeorwine could have posted on this thread to cause MNHQ to feel for the pearls ?

I wonder if it's the pelcgb word ?

cakeorwine · 09/08/2025 12:43

This reply has been hidden

This reply has been hidden until the MNHQ team can have a look at it.

Original poster
Sharingaroomtinightthen · 09/08/2025 12:13

SerendipityJane · 09/08/2025 10:56

Yes I saw that and clicked "thanks" to avoid diverting the thread from the pursuit of truth 😀

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‘The pursuit of truth’ 😂. I hope this thread will one day be studied as a true example of speaking truth to power (in a roundabout way).

OP posts:
SerendipityJane · 09/08/2025 10:56

BrickBiscuit · 09/08/2025 10:39

They've replied! "Let circulation at the end of year1= c. At the end of year2 it's 3c; at the end of year3 it's 2.25c. So the increase is 1.25c. This represents a percentage increase of 125% on c, the circulation at the end of year1. So none of the given options is correct."

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Yes I saw that and clicked "thanks" to avoid diverting the thread from the pursuit of truth 😀

BrickBiscuit · 09/08/2025 10:39

SerendipityJane · 05/08/2025 14:15

Did they also ask for the candidate guidance ?

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They've replied! "Let circulation at the end of year1= c. At the end of year2 it's 3c; at the end of year3 it's 2.25c. So the increase is 1.25c. This represents a percentage increase of 125% on c, the circulation at the end of year1. So none of the given options is correct."

irregularegular · 07/08/2025 11:27

Nchangeo · 06/08/2025 23:49

It’s 225%

You might want to read the two whole threads on this before wading in confidently.

irregularegular · 07/08/2025 11:25

Bjorkdidit · 07/08/2025 04:04

I can't believe people are still not seeing that percentage and percentage increase mean different things.

Even if you're one of the many who's proudly 'bad at maths', it's very basic pre GCSE level maths. It's not like they're asking they're asking for the standard deviation at the 95% confidence interval.

the civil service presumably employs specialist test setters for this (but not specialist mathematicians)

You'd think, but no. My department runs a specialist training course for industry and as experts we've recently been asked to review the exam question set that's been the domain of the type of middle aged middle class white man who doesn't know much and doesn't do much yet doesn’t ever get questioned on this someone who has now retired and its dreadful. Genuinely ambiguous questions and a marking scheme that doesn't always include the right answers and allocates marks in a really inconsistent way.

Not even for the big civil service entrance exams? That surprises me a bit. For comparison, Oxford University outsources multiple choice question setting for its "Thinking Skills Assessment test" for entrance for PPE, while setting its own more subject specific entrance tests.

BrickBiscuit · 07/08/2025 08:55

Nchangeo · 07/08/2025 00:40

I get why you are saying what you are saying also. It is a stupid question.

I am trying to think of how you could word the question better and I am stuck on that.

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If you increased 200 by 100% what do you get? 400, that’s what. 200% of 200. The only wording that could improve the question is a radio button with ‘125%’. Backtesting: none of the solutions is 125%. Its omission is an error, a mistake in the test. A stupid one. No need to be stuck - that’s it. The rest of the wording is fine.

cakeorwine · 07/08/2025 07:38

Nchangeo · 07/08/2025 00:05

Which is not an option in the answers. It’s oddly worded but the maths adds up and can be back tested.

It’s not any of the options over 300. It’s not 150. Logic deduces 225.
Backtest OPs original 200 to 450 is 200 x 2.25 =450. Done. Tick box move on.

It’s like VAT. That’s 20%. You want to work it out it’s x 1.2 (120%).

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So you've increased it by 20% when you multiply by 1.2

You've increased it by 20%
Your new amount is 120% of the original amount

Bjorkdidit · 07/08/2025 04:04

I can't believe people are still not seeing that percentage and percentage increase mean different things.

Even if you're one of the many who's proudly 'bad at maths', it's very basic pre GCSE level maths. It's not like they're asking they're asking for the standard deviation at the 95% confidence interval.

the civil service presumably employs specialist test setters for this (but not specialist mathematicians)

You'd think, but no. My department runs a specialist training course for industry and as experts we've recently been asked to review the exam question set that's been the domain of the type of middle aged middle class white man who doesn't know much and doesn't do much yet doesn’t ever get questioned on this someone who has now retired and its dreadful. Genuinely ambiguous questions and a marking scheme that doesn't always include the right answers and allocates marks in a really inconsistent way.

Original poster
Sharingaroomtinightthen · 07/08/2025 01:13

Nchangeo · 07/08/2025 00:40

What percentage represents the change?

What is the percentage increase? It’s crystal clear.

OP posts:
Nchangeo · 07/08/2025 00:40

What percentage represents the change?

Nchangeo · 07/08/2025 00:40

Sharingaroomtinightthen · 07/08/2025 00:20

It is 125% and the lack of right answer being given as an option doesn’t change that.

If you increased 200 by 100% what do you get?

Edited
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I get why you are saying what you are saying also. It is a stupid question.

I am trying to think of how you could word the question better and I am stuck on that.

Original poster
Sharingaroomtinightthen · 07/08/2025 00:20

Nchangeo · 07/08/2025 00:05

Which is not an option in the answers. It’s oddly worded but the maths adds up and can be back tested.

It’s not any of the options over 300. It’s not 150. Logic deduces 225.
Backtest OPs original 200 to 450 is 200 x 2.25 =450. Done. Tick box move on.

It’s like VAT. That’s 20%. You want to work it out it’s x 1.2 (120%).

Show quote history

It is 125% and the lack of right answer being given as an option doesn’t change that.

If you increased 200 by 100% what do you get?

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