There are n n\,n pens in a box.
6 of the pens are black and the rest are blue.
Maria takes a pen from the box at random and does not put it back. She then takes another pen at random from the box.
The probability that Maria takes two blue pens is 413\displaystyle \frac{4}{13}134
Show that 3n2−55n+182=03n^2 - 55n + 182 = 03n2−55n+182=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.