Chris's internet bill is $45 per month for 100 GB and $0.25 for every 1 GB over. His bill for this month is $65. How many GB over was Chris charged for on this bill?
Thoughts? Step-by-step reasoning:
Let G stand for the number of GB billed, so the total bill is $0.25G + $45 flat rate charge = $65 total bill. Now we will solve for G. $0.25G + $45 flat rate - $45 = $65 - $45. This simplifies to $0.25G = $20. $0.25G / $0.25 = $20 / $0.25. G = 80 GB were charged on this bill.
Thus, the answer is 80.