This is the question:

There are n sweets in a bag. Six of the sweets are orange. The rest of the sweets are yellow.
Hannah takes a sweet from the bag. She eats the sweet. Hannah then takes at random another sweet from the bag. She eats the sweet.

The probability that Hannah eats two orange sweets is 1/3. Show that n²-n-90=0

how much

the probability of hannah eating the first orange sweet is 6/n , the probability of her eating the second orange sweet is 5/(n-1). multiply 6/n by 5/(n-1), you get 30/(n^2 -n) ,equate this to 1/3 and make the equation a quadratic one ,you get n^2-n-90=0

gr8t