Imagine a hypothetical baseball player. Call him Alex. He fails a drug test that is known to be 95 percent accurate. How likely is it that he is really guilty? If you said 95 percent, you’re wrong.

The questions in this quiz are suitable for GCSE maths students studying converting decimals to fractions and percentages, converting fractions to decimals, converting percentages to decimals and ...

Writing one number as a percentage of another number is a common, everyday necessity. For example, it's used for calculating percentage scores on tests or working out costs on a project. A maths test ...