Let g be the number of GB.

The limited plan has a cost as follows:

C = 10(g - 5) + 55

C = 10g - 50 + 55

C = 10g + 5

We want to set the limited plan equal to the unlimited plan and solve for g:

10g + 5 = 70

Solve for

*g*in the equation 10g + 5 = 70

**Step 1: Group constants:**

We need to group our constants 5 and 70. To do that, we subtract 5 from both sides

10g + 5 - 5 = 70 - 5

**Step 2: Cancel 5 on the left side:**

10g = 65

**Step 3: Divide each side of the equation by 10**

10g/10 = 65/10

g =

**6.5**

Check our work for g = 6.5:

10(6.5) + 5

65 + 5

70