Ratios
A ratio is a comparison between two or more quantities. The colon is used to show ratios. 6 : 8 and 8 : 20 are ratios.
- Example 1. Share £60 in the ratio 2 : 3
- Example 2. The cost of going to the cinema is divided between two families in the ratio of 3 : 5 the smaller share is £60. How much is the total cost of the cinema?
- Example 3. The ratio of female employees to male employees is 3 : 7. If there are 84 female employees, how many male employees are there?
| (a) | Add the separate parts of the ratio to find the total number of parts 2 + 3 = 5 | |
| (b) | Divide 60 by 5 to find the value for each part: 12 | |
| (c) | Multiply each term in the ratio by 12: 2 x 12 = 24, 3 x 12 = 36 | |
| So £60 shared in the ratio 2 : 3 is £24 and £36 | ||
| (a) | Add the separate parts of the ratio to find the total number of parts 3 + 5 = 8 | |
| (b) | 3/8 of the cost was £60, so 1/8 is £20 | |
| (c) | The total cost is 8 x £20 = £160 | |
| So the total cost is £160 | ||
| (a) | Add the separate parts of the ratio to find the total number of parts 3 + 7 = 10 | |
| (b) | So 3/10 are female employees is 84, so 1/10 is 28 | |
| (c) | The number of male employees: 7 x 28 = 196 | |
| So the number of male employees are 196 | ||
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