A box contains black pens and blue pens. The ratio of the number of black pens to the number of blue pens is 5:2.
What fraction of the pens in the box are black?
Practise OCR GCSE Maths Writing a Ratio as a Fraction or Linear Function with exam-style questions for Foundation and Higher tier. 60 questions, matched to the OCR GCSE Maths (J560) specification and written in the written papers 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.