Answer:
Sonya pays a flat fee of $30 for her phone bill and pays $2 per gigabyte she uses per month. Put Sonya's bill as an equation with d being how many gigabytes she uses per month.
Explanation:
We get the flat fee of $30 from "30 + 2d" and the $2 per gigabyte from "30 + 2d" and since we want to find out Sonya's total bill, that's where the + in "30 + 2d" comes from. We want the variable to be d therefore d is how many gigabytes she uses per month.