n2-n-90=0

[AmexRuislip]

Is it Chris Hughton's new formation for next season

 

[GingerBeerMan]

n doesn't have to equal 10 (in the raw quadratic equation).

My mind is clearly ODD, because when I said I'd answered it in 15 seconds, I hadn't even spotted the obvious answer, but had answered -9.

-9 x -9 = 81

81 - -9 = 90

n = -9

I got -9 in a few seconds, didn't even think it'd be 10. But if done properly the quadratic equation should have been used which would have given us the right answers anyway. The solution Mac04 posted is really hard, if that's what they expected I'm not surprised people are complaining, that kind of stuff was on my uni statistics tests and it takes a lot of thought to think how to prove it.

 

[Daffy Duck]

I think it's testing the probability of whether we'll sign a new 20-goal a season striker.

Bit worrying that the answer is 0.

 

[SIMMO SAYS]

Who feckin cares

 

[Gwylan]

n doesn't have to equal 10 (in the raw quadratic equation).

My mind is clearly ODD, because when I said I'd answered it in 15 seconds, I hadn't even spotted the obvious answer, but had answered -9.

-9 x -9 = 81

81 - -9 = 90

n = -9

When I first saw this, I hadn't seen the whole question and thought it was how to solve the quadratic equation and I gave the same answer as HKFC

 

[SIMMO SAYS]

If I went to a shop and paid good money for -9 sweets I'd come back and shoot the f***ers

Good one

 

[hans kraay fan club]

When I first saw this, I hadn't seen the whole question and thought it was how to solve the quadratic equation and I gave the same answer as HKFC

Yay. We, and [MENTION=22906]GingerBeerMan[/MENTION] , can be ODD together.

 

[Elvis]

Who feckin cares

Poor old Hannah! she only wanted some bloody sweets.

 

[tinycowboy]

I thought this was quite tricky - when I was at school, we didn't do probability until A-level, I think. To deduce that (6/n) x (5/(n-1)) = (1/3) would appear to be not so straightforward (although it is guessable) if you haven't done probability. If you have done it, it's not too difficult.

 

[Dave the OAP]

I don't understand the question!

 

[Herr Tubthumper]

I thought this was quite tricky - when I was at school, we didn't do probability until A-level, I think. To deduce that (6/n) x (5/(n-1)) = (1/3) would appear to be not so straightforward (although it is guessable) if you haven't done probability. If you have done it, it's not too difficult.

I agree. I didn't do probability in O-level maths, but I did in O-level stats. But, if you have been taught probability at GCSE this question is, in my opinion, pretty basic.

 

[King Kayal]

It's easy.

90- 1, 90; 2, 45; 3, 30; 5, 18; 9, 10

(x+10) (x-9)

Therefore, X= -10 and 9

 

[Herr Tubthumper]

Poor old Hannah! she only wanted some bloody sweets.

I think it's code for drugs.

 

[yxee]

I'm not sure what's depressing, that schoolchildren can't do this, or that they moan and whine in such large quantities about it on social media afterwards.

 

[m20gull]

I thought this was quite tricky - when I was at school, we didn't do probability until A-level, I think. To deduce that (6/n) x (5/(n-1)) = (1/3) would appear to be not so straightforward (although it is guessable) if you haven't done probability. If you have done it, it's not too difficult.

Probability is now in GCSE. All that's needed is some algebra. Not sure what the fuss is about.

 

[GT49er]

The equation is dead easy, but what's all that guff about eating sweets for?

 

[Triggaaar]

Can you solve this?

I haven't done much with equations for 27 years, but yes, that took about 5 seconds (I appreciate many would have been faster).

 

[King Kayal]

I haven't done much with equations for 27 years, but yes, that took about 5 seconds (I appreciate many would have been faster).

The answer is not as simple as you think.

 

[SIMMO SAYS]

So for all the brainy people that have solved the puzzle- will it buy you a better car/house/partner

 

[Dunk]

I thought it was pretty hard as it goes.

Firstly it looked like a tree diagram question which would have thrown many candidates as the branches would have had 'n' and 'n-1' as denominators.
If they realised it was a case of multiplying (6/n)x(5/n-1) and making that equal to 1/3, it is then some tricky algebra to form the given equation.

The second part involved solving the given equation. It was a non-calculator question so the quadratic formula would have been tricky to use. It was factorisable however as (n-10)(n+9) = 0. There is then one final trick as only one of the two solutions made sense in context.

There were a few hard questions this year and round two on Monday. Everyone that used that exam board has the same exam though so it is fair. Good luck to anyone on here who has Paper 2 on Monday.