Maths test - to think Civil Service have it wrong?

[Sharingaroomtinightthen]

I’ve just applied for a Civil Service test. Part of it is passing a numerical test.

This is the question.

The answer is 125%. I’m sure of it.

If you start with £100, and in the first year it doubles it’s £200. So at the of year one it’s £200.

In year two it trebles to £600.

It then falls by a quarter in the third year to £450.

So end of year 1 - £200.

End of year 3 - £450.

It’s increased by 125%.

125% isn’t an answer option.

WIBU to email and tell them they’ve got it wrong?

Chat gpt also says it’s 125%.

I agree with OP. I also put the problem into Google and got the same result

Yes. But 400 being 200% of 200 does not mean it is a 200% increase. It’s is a 100% increase because it has increased by 100% (ie by 200).

I hope it's not a timed test!

That isn’t what the question is asking. It’s asking for the percentage increase.

Agree with OP. The percentage increase is 125%. The multiplier is 225%.

Same as finding percentage profits. If you buy for £200 and sell for £450, your profit is £250. Comparing £250 profit to your original purchase price of £200, that’s a 125% increase.

Oh, and sometimes the decisions that people make when a question could be ambiguous are more important - there isn't an option for 125%, so do they refuse to answer it, or do they think 'well, that must mean that they want the percentage of the starting figure that it represents, so I'll pick 225% as it's the only choice that could possibly fit'.

I doubt they're thinking this deeply, but it's always possible.

You are right, the question is wrong and you should tell them.

They thought they’d been smart, intending to design a question which could (with a little thought) be quickly solved without a calculator as 0.75 x 300%. But they didn’t ask what the circulation at the end of year 3 was as a percentage of the circulation at the end of year 1.

Instead they asked about the percentage increase, which is (0.75 x 300%) - 100%, as your worked example clearly shows.

Very disappointing that fast streamers are being tested by people who made this basic error. It’ll be some outsourced test, but someone should have picked it up. Really poor by them.

I have a first class maths degree from a red brick uni and I teach %’s and % changes as part of my job.
I agree with the OP.

I believe they want you to put 225% as the answer but that isn’t the answer to the question in the way it has been phrased.

And all are wrong. It’s whether to alert the recruiters that their test is wrong.

You start with 100%

But, as someone has made clearer now, you go UP 200% to the 300%

So the increase is 200%

But 400 is a 100% increase of 200.

If you double something, you increase how much you have by 100%

If you triple something, you increase how much you have by 200%

If we doubled 200, we would get 400. A 100% increase
If we tripled 200, we would get 600. A 200% increase

So we have 450. Which is clearly more than doubling, but less than tripling

@Sharingaroomtinightthen is correct. The increase from the end of Year 1 is 125%, but from the available options I would choose 225% rather than arguing that the question is incorrect.

Work to change the system from the inside once you have the job rather than have the moral high ground when telling people in the Job Centre about the career that got away. 😄

It isn’t and I spent an insane amount of time checking every last detail before resolving that the only solution left was that they’re wrong. It was extremely irritating submitting what I knew was a wrong answer.

Err, yeah! I think we are all familiar with multiple choice questions. The point of the AIBU is the OP thinks that none of the supplied options is correct.

Is that not obvious from the discussion or are you trying to make some other point?

Yes, I can understand that.

😆

This thread is hilarious. I think the person who set it has a finance background and is thinking in terms of returns, where it is fairly customary to not deduct the initial capital when calculating the return (so people talk about making a 2x return when they get back twice what they put in, including the initial capital).

But you are right with the question as stated. Circulation at the end of year 3 is 225% of circulation at the end of year 1, i.e. it has increased by 125%.

You are right that 110% of 100 is 110, but a 100% increase on 100 is 200.

You do not start with 100%.

Perfectly explained with a mathematical formula.

Obviously it is up to you OP what answer you give and if you email them.

Might be worth trying to think less rigidly and trying to understand how they are giving a different answer than you expected.

That can be a beneficial mindset to have rather than I'm definitely right, they're definitely wrong.

Maybe you could highlight to them that some of their questions were not worded as well as possible and were left open to interpretation.

I think if the increase is say 10 x 2 = 20 x 3 = 60/4x3 =45/30 =1.5 x 100 = 150%

You get these questions on GCSE papers

What percentage is 450 of 200?

How much bigger in percentage terms is 450 compared to 200?

2 different questions

I’m a Head of Maths in a secondary school - in complete agreement with OP, here!

Doubling is a 100% increase, but 200% of its original value. It clearly wants you to answer 225%, but it's also worded wrong. It has increased by 125%, but is now at 225%