There are some black socks and some white socks in a drawer.
The ratio of black socks to white socks is 2:12:12:1.
Two socks are removed at random from the drawer without replacement.
The probability that both socks are black is 37\displaystyle \frac{3}{7}73.
Work out how many white socks are in the drawer.
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.