Not too difficult, took me a bit longer than 5 seconds though

A few seconds. Factors (n-10)(n+9), so n = 10 or n = -9

It should be both, as I was taught.

Worries me too: at the risk of being controversial and showing my age, seems that kids** want it all served on a plate these days..

(took me about 10 seconds)

**I use the term loosely, to include University students too - I only recently retired from a Uni job and our students there for example expected printed copies of lecture notes handed to them rather than having to write their own. How do you learn that way ?

I know it is popular to view us as reactionary old gits, and actually kids today passing through "A" level and degrees get a good education.  And they do.  But it is dumbed down from what we did.  On the core subject of my very own live-in teacher it was a requirement when we sat our "A" levels to have grade 8 music theory to sit "A" level music.  Now it is only grade 5 music theory.  It is no longer necessary for GCSE music to actually be able to play music. 

Of course, in part that is because the world moves on.  So there are new subjects in the syllabus - composing using garageband or music maker, mixing, production techniques, electronic recording and the whole "music tech" thing.  Kids today can use programs like Cubase to produce complete music arrangements
But for all that - dumbed down.  Whilst Maths isn't my number one subject, having revised it to help the errant son (predicted grade U - achieved grade C) with his maths "A" level imagine my consternation to find calculus isnt taught at GCSE and is a new concept at "AS" level

(While we're on the subject, WTF did "AS" come from?)

My son got the correct answer in a minute - he is only just 10 though ...

When I was at school a few ~3 more capable lads, assumed to get grade A in the subject were entered for A level Special papers. Maybe a more modern form of the same thing. The same pupils were entered (and usually got entrance exams for Oxford or Cambridge)

If current education/question/pass standards are lower and fewer are passing perhaps the subject never gets mentioned if there are none likely to succeed in a year. Why depress the little pupils with comparisons to levels they have no chance of attaining.

There is no piscine connection to the question, and there's no catch in the question.
The question is what it is.

www.bbc.co.uk/news/education-33017299

If you look down to the video you will see what the students were expected to do without having their hands held.

The "maths" is pretty simple, and intuitive, but the full question asked for a lot more than a straight numerical answer for the value of n.

This was the question:


 So simply saying "10" doesn't answer the question, also the -9 answer is negated by the question.  It's a bit difficult to have less than zero sweets in the bag

This is an actual suggested "correct" answer