Impossible maths question

[Paddy]

https://www.youtube.com/watch?v=8Y0yolPv7tU

[centurian]

The question isn't What's n? It's to show the proof that the equation is correct. I don't remember doing any proof type stuff at O level, but it was a few years ago.

Correct - "proving" is different from "solving"

Put down "10" and you'll probably get 1 mark out of 5.

I don't recall doing proofs at GCSE Maths either.

[NotAllThere]

I couldn't see how it would be possible to misunderstand the question completely. Thanks for helping me out.

It must be something to do with an inability to either read the question or comprehend basic English.

[unixman]

Seemed easy but would be harder in the time/pressure of an exam room, and if you were 15 instead of 47.

[NotAllThere]

Seemed easy but would be harder in the time/pressure of an exam room, and if you were 15 instead of 47.

GCSEs are at 16, aren't they? But the fact that some people find exam pressure hard to deal with has no bearing on whether the question is difficult or not. Trouble is, I've a maths degree so it's a piece of cake ... but I also don't recall proofs at even that basic level at O level. Additional maths and A level, yes.

[Platypus]

but I also don't recall proofs at even that basic level at O level

It's not really a "proof" (in the general sense) it's more of a "show" (in this case) and yes my O level maths had plenty of this type of stuff: basic probability.

I thought the question was hard when I misread it and thought she'd taken 3 sweets and had to calculate the probability that two of the 3 were orange, so I was trying to remember how to combine nCr with probability if indeed that would have been right approach. When I re-read it, I realised it was much easier then that. But still an important lesson remembered: read the question and read it again, several times if necessary, so you don't end up trying to solve a different problem (such as, find the value of 'n').

[NotAllThere]

... and yes my O level maths had plenty of this type of stuff: basic probability.

Definitely basic. I just didn't recall... it was a long time ago!

[BrilloPad]

I like to eat my fruit gums black, red, green, orange, yellow.

If MF has left any...

[SpontaneousOrder]

The question isn't What's n? It's to show the proof that the equation is correct. I don't remember doing any proof type stuff at O level, but it was a few years ago.

Maybe that's the normal phrasing of the question. Having done my A level maths a long time ago (not as long ago as many mind you) it didn't seem obvious to me that they wanted you to show that that equation modelled the sweets scenario.

I.e. it's not surprising that the general public find a simple question so hard (re the article) when it's not the difficulty of the question that is problematic so much as the discerning what the actual problem to solve is, based on the wording of the question (for people who haven't had to worry about that kind of wording since school and are now reading it out of context). It's not necessary to arrive at that equation in order to solve the mystery, so it doesn't seem intuitively obvious why you even have to care about it unless you happen to have been studying those exact same kinds of questions for the last few years :s

[OwlHoot]

GCSEs are at 16, aren't they? But the fact that some people find exam pressure hard to deal with has no bearing on whether the question is difficult or not. Trouble is, I've a maths degree so it's a piece of cake ... but I also don't recall proofs at even that basic level at O level. Additional maths and A level, yes.

Seems to me quite subtle for a GCSE question, as it was a kind of inverse of the usual type of probability question where one is given the item counts and asked to find the probability.

Maybe it was a deliberate bowl out of the blue, to identify potential Mathematical Olympiad candidates or future codebreakers etc.