It's often useful to be able to find a percentage of a quantity. For example, you might be told that bus fares are going up by and you need to know how much more you will need to pay each week.
Here are a couple of ways you could do it:
Find of the quantity by dividing it by .
Find of a quantity by multiplying of the quantity by .
To find of a quantity you need to multiply of the quantity by .
Rakesh has a box containing pens. of the pens are red.
How many red pens does the box contain?
You need to find of .
So of is
Find the percentage of a quantity by multiplying that quantity by the percentage expressed as a fraction.
This combines the division and multiplication of Method 1 into one sum.
Q1. In a class of pupils, live in a flat. How many pupils live in a flat?
Q2. Last year Sam earned . This year her pay has increased by .
a) By how much money has Sam's pay increased?
b) What is her new salary?
A1. is equivalent to
Therefore pupils live in a flat.
a) Method 1:
b) Method 2:
So Sam's new salary is: