There are n n\,n counters in a bag.
5 of the counters are red and the rest are blue.
Chloe takes a counter from the bag at random and does not replace it. She then takes another counter at random from the bag.
The probability that Chloe takes two blue counters is 16\displaystyle \frac{1}{6}61
Show that n2−13n+36=0n^2 - 13n + 36 = 0n2−13n+36=0
Find the value of nnn.
43 exam-style questions on OCR GCSE Maths Probability Equation Questions. Each one has a worked solution and a mark scheme showing where the marks go.