In this lesson, let’s look at finding percentage increase or decrease in a quantity. This is common in real-life situations such as calculating discounts, profit, salary increase, or population growth, etc.
Percentage Increase
% increase =\(\frac{increase}{original} \times 100\%\)
Percentage Decrease
% decrease =\(\frac{decrease}{original} \times 100\%\)
Percentage Formulas for Sales
Percentage is often used in sales and finance. Let’s look at some common percentages, and also some common terms when looking at sales.
Common Terms used in Sales
Marked Price (Usual Price or List Price or Original Price): The price an item is sold for before any discount.
Discount : The reduction in the selling price of an item from its marked price.
Selling Price: The price an item is sold for.
Cost Price: The price the seller buys the item for.
Profit: Profit is made when the seller sells the item at a price more than its cost price. Profit = Selling Price – Cost Price
Loss: Loss is made when the seller sells the item at a price less than its cost price. Loss = Cost Price – Selling Price
Goods and Services Tax (GST): GST is a tax added to the price of goods and services sold to consumers. It is a consumption tax collected by the government. The current GST rate in Singapore is 9%.
Percentage Discount
% discount =\(\frac{discount}{original price} \times 100\%\)
Percentage Profit
Profit = Selling Price – Cost Price
% profit =\(\frac{profit}{cost price} \times 100\%\)
Percentage Loss
Loss = Cost Price – Selling Price
% profit =\(\frac{profit}{cost price} \times 100\%\)