Interesting Fact - GCSE Maths #EdexcelMaths

The Twitter hashtag #EdexcelMaths popped up all over the internet following  the GCSE maths exam paper from Edexcel (part of the Pearson group).  It contained a question about someone called Hannah and her bag of orange and yellow sweets, and caused a hilarious Twitter storm.

(Tweets like this:-

flooded the net over the following question:-

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

According to the Independent, this is the answer:-

There are 6 orange sweets and n sweets overall. So, if Hannah takes one, there is 6/n chance of getting an orange sweet. When she takes one,, there is one less orange sweet and one less overall meaning that the probability is now (6-1)/(n-1)=5/n-1.

To find the probability of getting the orange sweet both times, multiply the two fractions: 6/n* 5/n-1 =30/n^2-n.

It shows the probability of taking two orange sweets (1/3) is: 1/3=30/n^2-n.

The denominators then need to be the same, so multiply 1/3 by 30 which would then make 30/90=30/n^2-n.

Discounting the 30 on both sides of the equation makes n^2-n=90. By moving 90 onto the other side of the equation, it will equal zero.

There was also a question about the volume of two pieces of cheese, which elicited the following response from Joe Reeves :-

Why did Jane bother cutting her cheese into two different shaped cuboids if she wanted the same volume?

Another question mentioned pencils, which brought the following response from someone called Brittany:-

"I'm going to stab myself in the eye with all of those pencils John bought for the conference."

Of course students in China would laugh in the face of this.  They are sitting the Gaokao, which lasts for two days and is dubbed the "the world's toughest exam".  Maybe Pearson wanted to steal their thunder.

I'm so glad Twitter didn't exist when I sat my exams.)