A ratio is a comparison of two numbers or quantities by division. For example, suppose a movie theater has 200 men and 300 women. Below we show three ratios that we could write from this situation.
The ratio of men to women is 200/300
The ratio of women to men is 300/200
The ratio of men to the total number of people is 200/500
This means that for every 2 men, there are 3 women.