Becky needs to choose a new cell phone plan. She has 2 choices. Carolina Cell offers a monthly fee of $20.79 and $2.00 for each gigabyte of data used. Sanford Cell offers a monthly fee of $22.89 and $1.50 for each gigabyte of data used. What is the amount of gigabytes, to the nearest tenth, when both plans would cost the same?

4.2 gigabytes

Step-by-step explanation:

To find the answer, you need to write an equation where the cost of Carolina Cell is equal to the cost of Sanford Cell:

20.79+2x=22.89+1.50x, where x is the number of gigabytes used.

Now, you can solve for x:

2x+1.50x=22.89-20.79

0.5x=2.1

x=2.1/0.5

x=4.2

According to this, the answer is that both plans would cost the same  when 4.2 gigabytes are used.