'Percent' means 'out of 100'. If 90 per cent of the population owns a mobile phone, this means 90 out of every 100 people have one. The symbol '%' means per cent.
Finding percentages
A percentage is a fraction of 100.
30% (30 in each 100) as a fraction is 30/100
30% as a decimal is 0.3.
Often, in real life - and maths exams - you must find a percentage of a quantity. First, write the percentage as a fraction or a decimal, then multiply by the quantity.
Have a look at this question:
- Question
Find 40% of £50.
- Answer
First, write 40% as a fraction: 40% = 40/100 = 4/10 = 2/5
Now multiply by the quantity:
2/5 × 50 = £20.
Practise converting percentages to fractions. Then try the questions below.
- Question
Sarah is buying a pair of jeans. The original price was £75, but there is a discount of 30%. How much will the discount be?
- Answer
Discount = 30% of 75
= 30/100 × 75
= 0.3 × 75
= £22.50
(Note that if the question asked for the discount price, you would subtract the discount from the original price : £75 - £22.50 = £52.50.)
Sometimes both the percentage and amount of money will not be whole numbers.
- Question
A car costs £9,999.90 before VAT (value added tax). Work out the cost of the VAT if it is charged at 17.5%.
- Answer
VAT = 17.5% of £9,999.90
= 17.5/100 × 9,999.90
= 1,749.9825
Since the answer is a price, it must be rounded to two decimal places.
The answer is £1,749.98
Profit and loss
People often buy something at one price, and sell it on for another - eg, when they are selling things at a car boot sale.
If the selling price is greater than the buying price, a profit is made.
If the selling price is less than the buying price, there is a loss
Income Tax
People pay tax on the income they earn. The basic rate of income tax is 22%.
VAT
Value Added Tax is added to the cost of most things you buy. It is charged at 17.5%.
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