There are 30 pens in a box.
12 of the pens are black. 7 of the pens are green. The rest of the pens are red.
One of the pens is chosen at random.
Find the probability that the pen is red.
18 exam-style questions on Oxford AQA IGCSE Maths Probability. Each one has a worked solution and a mark scheme showing where the marks go.