Question

Under his cell phone plan, Bentley pays a flat cost of $64.50 per month and $4 per gigabyte. He wants to keep his bill at $78.90 per month. How many gigabytes of data can he use while staying within his budget?

Answer 1

3.6 gB

Explanation:

You can think of this question in terms of the y = mx+b equation.

$78.90 is y because it is the total amount per month, $4 is m because it is the cost per gB, and $64.50 is b because it is the flat rate.

78.9 = 4x + 64.5

4x = 14.4

x = 3.6 gB of data (or 3 if it wants a whole number)