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Ratio and sharing
Ratios compare amounts. Sharing in a ratio is one of the most common exam questions.
Simplifying
Divide every part by the highest common factor.
12 : 18 = 2 : 3
Make units the same first: 50p : £2 = 50 : 200 = 1 : 4
12 : 18 = 2 : 3
Make units the same first: 50p : £2 = 50 : 200 = 1 : 4
Sharing in a ratio
1. Add the parts. 2. Divide the total by the number of parts. 3. Multiply.
Share £60 in the ratio 2 : 3: 5 parts, £12 per part, so £24 and £36.
Share £60 in the ratio 2 : 3: 5 parts, £12 per part, so £24 and £36.
Ratio to fraction
In the ratio 2 : 3 the first share is 25 of the total.
If you know one share, find one part first: 2 : 3 and the smaller share is £24, so one part is £12.
If you know one share, find one part first: 2 : 3 and the smaller share is £24, so one part is £12.
Red and blue beads are in the ratio 3 : 5. There are 40 beads. How many are blue?
- 3 + 5 = 8 parts
- 40 ÷ 8 = 5 per part
- Blue: 5 × 5 = 25
Answer: 25
Simplify by dividing by the HCF, with units the same. To share, add the parts, find one part, then multiply.
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