Ratios can be a bit tricky to understand. They look like this:
1 : 5
What this means is for every one there are five.
If you get confused by a ratio read it as ‘for every…’ ‘there are…’.
If we are asked to find the ratio of girls to boys in a room where there is 1 girl and 5 boys. The ratio of girls to boys is 1 : 5.
For every 1 girl there are five boys.
The ratio of boys to girls in the same room is 5 : 1. For every 5 boys there is one girl.
If there were 4 boys and 2 girls in the room the ratio of boys to girls would be 4 : 2.
If the room filled up to 12 people but the ratio of boys to girls remained the same at 4 : 2 there would now be 8 boys and 4 girls.
Do you see why? The number of people in the room has doubled but the ratio stayed the same, so the number of boys and girls must also double.