On 05/06/15 15:01, Tim Watts wrote:

The actual question was:

Hannah has 6 orange sweets and some yellow sweets.
Overall, she has n sweets.
The probability of her taking 2 orange sweets is 1/3.

Prove that: n^2-n-90=0

I should add, that is a paraphrased version (as are all of them as
they've been typed from memory).

For the avoidence of doubt, Hannah takes a sweet and it is orange. She
eats it and takes another, which is also orange.

The probability of her managing to do this is stated as being 1/3.