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Simplifying ratios

can be fully simplified just like fractions. To a ratio, divide all of the numbers in the ratio by the same number until they cannot be divided any more.

Example

Simplify \(6:12\).

Divide both numbers by 2:

\(6:12 = 3:6\)

Divide both numbers by 3:

\(3:6 = 1:2\)

A quick way of doing this in just one step is to divide by the of all the numbers in the ratio. In this example, the highest common factor of 6 and 12 is 6. Dividing each number by the HCF:

\(6:12 = 1:2\)

Image gallerySkip image gallerySlide 1 of 7, 6 red:12 yellow, A ratio of 6:12 with 6 red coloured counters and 12 yellow coloured counters spread out horizontally

Question

Simplify these ratios fully:

  1. \(4:6\)
  2. \(9:12\)
  3. \(5:10:15\)