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Ratio
What a ratio tells you
A ratio compares parts. 3 : 2 means for every 3 of the first thing there are 2 of the second. It does not tell you the totals on its own.
Sharing an amount
Add the parts to get the total number of parts. Divide the amount by the total parts to find what one part is worth. Then multiply up for each share.
Simplifying
Divide every number in the ratio by the same value, just like a fraction. 12 : 18 becomes 2 : 3 after dividing by 6.
Worked example
Share £45 in the ratio 4 : 5.
- 1First check what's being asked: both shares, in pounds.
- 2Total parts: 4 + 5 = 9.
- 3One part: 45 ÷ 9 = 5.
- 4Shares: 4 x 5 = 20 and 5 x 5 = 25, so £20 and £25. They add back to £45.
Answer: £20 and £25