A box contains purple discs and orange discs.
The ratio of purple discs to orange discs is 5:15:15:1.
Two discs are picked at random from the box.
The probability that both discs are orange is 166\displaystyle \frac{1}{66}661.
Work out the total number of discs in the box before any were picked.
Practise Eduqas GCSE Maths Probability Equation Questions with exam-style questions for Foundation and Higher tier. 28 questions, matched to the Eduqas GCSE Maths (C300QS) specification and written in Component 1 and Component 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.