Four ninths of the kids walk to school if 248 kids walk to school what is the total school population

You solve it like this:                      You put in a format where you cross-mutiply 
     4   248          248 * 9                 the numbers then divide to get x, or in this 
     9     x               = 2232               case, total school population.
                                                                248 kids / 558 total school 
4x = 2232                                               population
     x = 558

19 - 30

20 - 234/12

hope this will help you