8. In each case below, decide which option you would prefer to be given. Justify your answer with mathematical calculations. 3
Taking it FURTHER
(i) 10% of €4 (ii) 3
or
__ 5 of 2 pizzas
(iii) 15% of 60 sweets or
__ 4 of 80 cents
or 28% of 5 pizzas 1
__ 8 of 72 sweets
5.5 Percentages in context
Some of the most common percentages in context questions involve money. Areas include percentage profi t/loss and value added tax (VAT).
Percentage profi t/loss
When calculating the percentage profi t/loss we need to know some information: the cost price and the selling price.
The cost price (CP) is the amount for which an article is bought. The selling price (SP) is the amount for which an article is sold.
For example, if a person buys an item for €15 and sells it for €20, the cost price is €15, and the selling price is €20.
If the selling price is greater than the cost price, then there is a gain, or profi t. Profi t = selling price – cost price
If the selling price is less than the cost price, then there is a loss. Loss = cost price – selling price
The formula to calculate the percentage profi t/loss is: Percentage profi t/loss = profi t / loss
Worked example 1 Paul bought a bike for €200. The following year, he sold it for €160. (i) Did Paul make a profi t or a loss? (ii) How much did Paul make/lose? (iii) Calculate Paul’s percentage profi t/loss.
Solution (i)
(ii) (iii)
________ cost price × 100
By the end of this section you should be able to:
● use percentages in everyday situations including percentage profi t/loss and VAT
Section A Introducing concepts and building skills