How to find relative frequency of a set of numbers

Aresearch group wants to find the opinions’ of city residents on the construction of a new downtown parking garage. what is the population of the survey downtown shoppers downtown visitors downtown workers city residents

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?

2x minus y equals 6, x plus y equals negative 3