Percentages

A percentage is a fraction of 100. Percentages are used often in everyday life; a news report entitled '40% of teenagers drink fizzy drinks daily' and a shop hosting a 30% off sale are both examples of this. Percentages will crop up in your exam too, so it's important to familiarise yourself with the main types of percentage questions the examiners expect you to answer.

Finding x% of y
To find x% of y, simply divide y by 100 and multiply the result by x. Here is an example of this question type:

Find 35% of 60
 * First, divide 60 by 100:

$$60 \div 100 = 6$$


 * Next, multiply 0.6 by 35:

$$0.6 \times 35 = 21$$

We now have the answer, which is 21.

Finding x as a percentage of y
To find x as a percentage of y, multiply x by 100 and divide the result by y. Below is a typical example of this question type:

Express 45 as a percentage of 225
 * To start off, multiply 45 by 100:

$$45 \times 100 = 4500$$


 * Divide 4500 by 225 to find the answer:

$$4500 \div 225 = 20%$$