1 Using percentages
At the end of Week 5 you were calculating percentages from different sets of information – for example, you worked out what percentage of children in a group preferred to visit the zoo. This week, you’re going to start by trying a refresher activity before moving onto some new ideas.
You will definitely find a calculator useful for Activity 1, which involves population figures.
Activity 1 Writing one number as a percentage of another
- a.In 2012, the population of the European Union was about 503 663 601, and the total population of the United Kingdom was about 62 989 551. What was the population of the UK as a percentage of the total population of the European Union?
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To find the percentage, you write the numbers as a fraction and multiply by 100.
First write the two numbers as a fraction:
Then multiply by 100, to give:
The answer is rounded to 1 decimal place. By necessity, population figures are estimates – so showing the answer any more accurately would not make sense in this case.
Rounded to 1 decimal place, the population of the UK was 12.5 per cent of the total population of the European Union in 2012.
- b.Now looking at a smaller member state – Luxembourg, which had a population of around 524 853 in 2012. Find the population of Luxembourg as a percentage of the total population of the European Union, rounding your answer to 1 decimal place again.
Population percentage =
The population of Luxembourg, rounded to 1 decimal place, was about 0.1 per cent of the total population of the European Union in 2012.
Hopefully, you felt confident from your practice last week in completing this refresher activity. If it proved slightly more challenging, you may find it useful to look back at Section 3 'What percentage is it?' in Week 5.
Another way that you will often see a percentage used is when saying what a certain percentage of a number is: for example, being advised when going on holiday that 10 per cent of the cost of a flight is a fuel surcharge, or that 15 per cent of a group of people having a preference for a certain food type. In the next section, you’ll look at how to use this information to find the actual numbers involved. Again, you should recognise some of these techniques from Week 5.