Answer to the GCSE question that stumped Britain's students
BRITISH student taking Edexcel's GCSE Maths paper took to Twitter to vent their frustration over a problem involving how many sweets a girl called Hannah has.
So, what was 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.