Frodo and sam are photographers. they take pictures of seniors for high school yearbooks. they charge a standard fee for taking the pictures. there's also a charge for each set of prints ordered. so the number of sets of prints determines the total cost.

let s stand for the sets of prints ordered. write the rule that describes a student's total cost.

sets of prints total cost
0 $15
1 $19
2 $23
3 $27