Tea bags are sold in small boxes and large boxes. There are 150 tea bags in a small box. There are 320 tea bags in a large box. Oliver buys x x\,x small boxes and y y\,y large boxes of tea bags.
Write an expression for the total number of tea bags Oliver buys.
267 exam-style questions on OCR GCSE Maths Writing an Expression. Each one has a worked solution and a mark scheme showing where the marks go.