How do i find the solution to this?

One-third of the people from country a claim that they are from country b, and the rest admit they are from country a. one-fourth of the people from country claim that they are from country a, and the rest admit they are from country b. in a combined census of the two countries, one-half of the total claimed to be from a. what is the ratio of the populations of country a to that of country b.

Ineed here’s a picture of the question

1/2+1/6-3/4 simplify the given expression leaving the answer in improper fraction form.