Answer:
To stay within budget, she must use 4.5 gigabytes.
Explanation:
Giving the following information:
Under her cell phone plan, Sofia pays a flat cost of $58.50 per month and $4 per gigabyte. She wants to keep her bill at $76.50 per month.
First, we need to establish the total cost formula:
Total cost= 58.5 + 4*x
x= number of gigabytes
Now, we isolate x:
76.5= 58.5 + 4x
18/4= x
4.5= x
To stay within budget, she must use 4.5 gigabytes.