psychology aqa a level

I was doing a past exam paper for revision, and I was asked to calculate the ratio of something, is this required to know as i have never done this in class

what was the question?

In 1987, a survey of 1000 young people found that 540 said they smoked cigarettes, whilst
460 said they did not. In 2017, a similar survey of another 1000 young people found that
125 said they smoked cigarettes, whilst 875 said they did not.
0 2 Calculate the ratio of smokers to non-smokers in 2017. Give your answer in simplest form.
Show your workings.