Question

David has a smart phone data plan that costs $30 per month that includes 6 GB of data, but will charge an extra $10 per GB over the included amount. How much would David have to pay in a month where he used 4 GB over the limit? How much would David have to pay in a month where he used went over by xx GB?

Answer
Attempt 2 out of 2

Total cost when over by 4 GB:
Total cost when over by xx GB:

Answer 1

Answer: Total cost when over by 4 gb: 70 dollars

Total cost when over by xx gb: (30+10*xx) dollars

Explanation: He used 30 dollars plan which had 6 gb. Eventually he used 4gb over limit. According to question, it would cost 10 dollars more per gb if used above limit.

He used 4 gb more than limit. Hence,

it would cost him (4*10) dollars more. Thus total cost is (30+4*10) i.e. 70 dollars.

For the next sub-question, using the same logic, we get the expression and the final answer as:

(30+10*xx) dollars.