Presentation on theme: "PERCENTAGES. WHAT IS A PERCENTAGE (%) ? A percentage is a number represented as a part of 100. How do we calculate a percentage of an amount? Write the."— Presentation transcript:
WHAT IS A PERCENTAGE (%) ? A percentage is a number represented as a part of 100. How do we calculate a percentage of an amount? Write the percentage as a fraction with 100 as the denominator e.g. 40% = or write the percentage as a decimal fraction e.g. 40% = 0,40
A PRACTICAL EXAMPLE: WORKING OUT PERCENTAGES OF AMOUNTS… 62 300 people were at the Nelson Mandela Stadium to watch the Super Kings and 30% purchased a hotdog for dinner. Using a calculator, let us work out how many people purchased a hotdog. 30% = 30 ÷ 100 = So x 62 300 = 18 690 people purchased a hotdog.
A PRACTICAL EXAMPLE: WORKING OUT PERCENTAGES OF AMOUNTS… There are 42 350 people living in South Africa and 40% live in rural areas. Using a calculator, let us work out how many people live in rural areas: 40% = 40 ÷ 100 = So x 42 350 = 16 940 people live in rural areas.
BUT HOW DO WE WORK OUT ONE AMOUNT AS A PERCENTAGE OF ANOTHER AMOUNT? For example, if we have made 160 scarves and we sell 120, what is the percentage of scarves that we sold? We work this out as follows: 120 of the 160 scarves were sold so we need to divide the number of scarves sold by the number of scarves made: 120 ÷ 160 = 0,75 We then multiply this decimal fraction by 100 to give us the percentage: 0,75 x 100 = 75% So 75% of the scarves were sold.
PERCENTAGE DISCOUNTS AND INCREASES Some definitions: Cost price : The amount that the retailer pays for a product or service Marked price: This is the price of the product or service. Selling price: This is the price after discount. Profit: Sale price − cost price.
When there is a percentage discount in a product or service, the amount decreases. When there is a percentage increase in a product or service, the amount increases.
A PRACTICAL EXAMPLE: The price of a tub of ice-cream is R 46,99. If the price rises by 10%, how much will it cost? The new price is therefore R 46,99 + (10% of R 46,99) = R 46,99 + R 4,70 (rounded off) = R 51,69
A PRACTICAL EXAMPLE: Guess Jeans have a 20% on all their jeans. If one pair of Guess jeans costs R 499,00, what will you pay for a pair now? You will only pay 80% (100% - 20%) Thus 80% of R 499,00 = x R 499,00 = R 399,20 – that is the new price OR 20% of R 499,00 = x R 499,00 = R 99,80 – this is the discount amount So you pay R 499,00 – R 99,80 = R 399,20 – that is the new price