Many people have the notion that UK British GCSE is very easy, but there seems to be a very tough Probability question that has appeared!
Here’s the question on the test, which was set by the British education and examination board Edexcel
There are n sweets in a bag. Six of the sweets are orange. The rest of the sweets are yellow. Hannah takes a random 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.
This is really one tough question for 15, 16 year old kids.
Do try it out, and if you are stuck you can check out the solution by Professor Ian Dryden, the head of mathematical sciences at the University of Nottingham, at the link above.
Probability Demystified 2/E
Check out this book to get enlightened on the mysterious topic of probability.