4.2 Percentage increase or decrease


Discuss and discover


Anita has a job in which she earns €100 per week. Her employer is very pleased with her work and gives her a 50% pay rise. A while later, the employer has to reduce everyone’s pay and tells Anita he will have to reduce her wage by 50%. Anita thinks this is okay, and she will still earn €100 a week. After all, a 50% increase is the same as a 50% decrease. Is she correct?


What have you discovered about percentage increases and decreases?


It is important to understand the diff erence between a percentage increase and a percentage decrease. Although the percentage might be the same, it is the actual amount of money or other items which needs to be considered.


Percentage increase or decrease = change ( increase or decrease ) ____________________ original value


Worked example 1


A property developer bought an apartment block for €2 ⋅ 5 million. Seven years later, he sold it for €1 ⋅ 8 million. What was the percentage decrease in the value of the property?


Solution × 100


Note: A decrease in the price or the value of goods is also known as depreciation.


By the end of this section you should be able to: ● calculate percentage increase or decrease


You must put a % symbol after your fi nal answer.


Worked example 2


A local football team were playing in a league. On a particular Saturday, there were 2 500 spectators at their match. The following Saturday there were 3 300 spectators at their match. Calculate the percentage increase in the number of spectators at the second match.


Solution


82


Linking Thinking 2


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