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?

But you've completely disregarded the 300% increase in yr 2.

Hence the quest from not between

It's not my maths that needs questioning sorry

I agree, badly worded Q and they have made an error.

I assume someone has meant that it went up to 300% (trebled) in Y2 then fell by a quarter (-75%) and then taken that to mean it has increased by 225%

£400 is an 100% increase on £200 - so 200% of £200.

Would they? Seriously?

I know there was a distinct lack of maths teachers at my DS school

Haven’t a clue. They were all wrong so I chose one randomly.

100 is 100% of 100.
450 is 225% of 200 (i.e. 200 x 2.25) which is an increase of 125%, as the OP said.

It doesn't really matter which number you use to make it more tangible, but obviously 100 is fairly easy to deal with.

If I have 200 and it triples, I get 600

Then the circulation drops by a quarter

A quarter of 600 is 150

So you have 450

Can you explain your thinking? With calculations

They’re asking for the percentage increase from the end of year one to the end of year three, are they not?

The percentage increase between 200 and 450 is 125%, is it not?

@Sharingaroomtinightthen Re whether to tell them….I personally would have to. It would niggle away at me otherwise!

HOWEVER — I have many times been told that the civil service, even for (especially for) the nicher fast stream roles, doesn’t like people to be too clever. 2:1s are preferred to Firsts; team workers to geniuses, leaders, mavericks or those whose thinking style is a little too intellectual or individualist. (Even when I have several times been a referee for civil service developed vetting, the vetters are very keen to check that the candidate is not too intellectual/too much of an individualist, and the successful ones are generally even now still the good eggs who are bright but not too bright, follow the rules and take instruction from management, rather than people who go out of their way to make a stand on being right or point out where their managers are wrong….)

On this basis, maybe you shouldn’t stick your neck out to point out that the test is wrong 😆 That is, if you want the job…?

The poster above complaining about the public sector was being egregious, but in all seriousness there might be something in that. If the test being wrong annoys you (and it would annoy me — and I’m not a good fit for the CS because I always have to point out where I’m right and someone in authority is wrong 😆) — might you genuinely be better off doing something in private sector consultancy or third sector or similar, where you can follow your more individual instincts, rather than the civil service, where you’re very much trained to suppress them?

If I have £200 and then I make some money and then lose some money and end up with £450, no civil servant can tell me that the amount of money I have has increased by 225%!!!

The increase of year two has not been disregarded.

It's not 125%

Times something by 100% and it DOES NOT DOUBLE IT, that is the part you are missing OP, it's really important, it's the mistake people are making on here when they say it is 125%.

Trust me, I work in design and 100% is the baseline, if you print something at 100% you are not changing the size at all, if you print something 90% you will make it slightly smaller, if you print at 110% you will make it slightly bigger.. 100% is the baseline.. do it on the calculator if you are not sure.

100 x 50% = 50
100 x 100% = 100
100 x 200% = 200

so if you have 100 and you times it by 100% it is still 100.

start of year one 100
end of year one 200
year two 600
end of year three 450

450 / 200 = 2.25 (225%)

For all the people saying 125%, just work it out to see that it is wrong...
The question wants the percentage increase between £10 and £22.50.
£10 x 125% = £12.50. INCORRECT
£10 x 225% = £22.50 CORRECT

Why are you working out the increase from 20 to 90? The question asks for the % increase from the end of Y1. Using your figures, at the end of Y1 the number was 40 (not 20). So we want the % increase from 40 to 90. Which is 125%.

Make it even simpler. Call the figure at the end of Y1 1000. After one year it has trebled, so at the end of Y2 the sales figure is 3000. It then falls by a quarter, so at the end of Y3 the sales figure is 2250.

The sales figure has gone up from 1000 to 2250, which is a 125% rise.

150%

@Steph7181 all these recruitment aptitude tests are outsourced, to private sector concerns naturally.

Yes, but they’re asking what the percentage increase is.

If you increase 100 by 100%, what do you get?

If you multiply 100 by 1, you get 100.
If you multiply 100 by 2, you get 200.

If you INCREASE 100 by 100%, you get 200

200/ 100 = 2

So it's a 100% INCREASE

If you multiply something by 2.25, you get 225% of that number but you have INCREASED it by 125%

90/40 = 2.25, not 1.25, ergo: 225%

I think given the answers its poor english wording

Sales projections start at zero with a benchmark of a fixed point in time.

As a concept in sales to say you met the 100% target sounds better than 0% change.

Plus because if you are running projections on sales you have to run the cost (ignoring step/fixed cost) etc so mental maths is easier....

Surely you aren’t claiming that public sector productivity isn’t a huge drain on the economy?

OP, you're wrong. Go onto the calculator on your phone and type in 200 x 225% (including the percentage sign) and it equals 450.

225% is the correct answer.

It's 225%.

If you increase 40 by 100%, what do you get?

Do you agree that 80 is 100% more than 40?

And 120 is 200% more than 40?

So what is 90?

Start = 100
End of year 1 = 200
End of year 2 = 600
End of year 3 = 450 (600 - 150)

200 -> 450 = 225%