A ratio is used to compare two quantities. The quantities should be in the same units.
Part ofMathsNumeracy
Follow this example of splitting a quantity in a given ratio.
\(\pounds30\) is shared between Ken and John in the ratio \(2 : 1\).
How much does each get?
If something is split in the ratio \(2 : 1\), then there are 3 'parts' altogether.
\(1\,part = \frac{{30}}{3} = \pounds10\)
Ken has 2 parts = \(2 \times \pounds10 = \pounds20\)
John has 1 part = \(1 \times \pounds10 = \pounds10\)
Use the same method of working to solve this question.
There are 180 pupils in a school year.
The ratio of left-handed pupils to right-handed pupils is \(1 : 8\).
How many pupils are right-handed?
The ratio is \(1 : 8\) so there are 9 'parts' altogether.
\(1\,part = \frac{{180}}{9} = 20\)
Left-handed pupils = 1 part = \(1 \times 20 = 20\).
Right-handed pupils = 8 parts = \(8 \times 20 = 160\).
