Can somebody help me with this question

Find |−5|. a. −5 b. 5 c. one-fifth d. –one-fifth !

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.

Use set builder notation to represent the following set: { -3, -2, -1, 0}