Percentage Change (Edexcel GCSE Maths)
Revision Note
Percentage Change
How do I find a percentage change?
The multiplier that was used for a percentage change can be found using the formula:
The value of corresponds to the multiplier for the percentage change
1.05 corresponds to an increase by 5%
0.75 corresponds to a decrease by 25%
Alternatively you can use the formula:
Percentage Change =
A positive value is a percentage increase
An answer of 12 means an increase of 12%
A negative value is a percentage decrease
An answer of -28 means a decrease of 28%
How do I find a percentage profit or loss?
Similar strategies to the above can be used to find the percentage profit or loss
Shops buy or produce items at a "cost price" and sell them at a "selling price"
Using a multiplier method:
1.05 corresponds to a 5% profit
0.75 corresponds to a 25% loss
Alternatively you can use the formula:
Percentage Profit =
A positive value is a profit
An answer of 12 means a 12% profit
A negative value is a loss
An answer of -28 means a 28% loss
Examiner Tips and Tricks
Use "common sense" to check your answer!
If an item is sold for more than it was bought for, you are expecting a profit, not a loss
Worked Example
The number of students in a school changes from 250 to 310. Describe the percentage change in number of students.
Method 1
Use the formula
This multiplier corresponds to an increase of 24%
A percentage increase of 24%
Method 2
Use the formula Percentage Change =
The value is positive, so this is a percentage increase
A percentage increase of 24%
Worked Example
Sophie purchases a car for $ 8000 and sells it several years later for $ 5600. Describe the percentage profit or loss on the car.
Method 1
Use the formula
This means the selling price was 70% of the cost price, so a loss of 30%
A loss of 30%
Method 2
Use the formula Percentage Profit =
The value is negative, so this is a percentage loss
A loss of 30%
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