Ratios

When we express ratios in words, we use the word "to"--we say "the ratio of something to something else." Ratios can be written in several different ways: as a fraction, using the word "to", or with a colon.

Writing a comparison in the form of a ratio

A farmer has 3 cats and 7 dogs. Write down the ratio of:

a) cats to dogs.

b) dogs to cats.

The Answer:

a)         Cats to Dogs

            Cats = Dogs

                 3 : 7

b)         Dogs to Cats

            Dogs = Cats

                  7 : 3

Splitting a quantity in a given ratio

$30 is shared between Ken and John in the ratio 2:1. How much does each get?

The Answer:

(If something is split in the ratio 2:1, then there are 3 'parts' altogether.)

Using a ratio

The ratio of girls to boys in the school disco was 3:1. If there were 50 boys there, how many girls were at the disco?

The Answer:

Boys = 1 part = 50 students

Girls = 3 parts = 3 x 50

        = 150 students

There were 150 girls at the disco