Answer:
a. $70
b. $(40 + 10x)
Step-by-step explanation:
The standard cost of the charges is $40 per month but an extra $10 per GB over the included amount.
a. Firstly the cost for a month in which he uses 3GB over the limit
we have a standard of $40, then he has to pay $10 per GB for the 3GB over the limit.
Thus the cost of the 3GB is $10 * 3 = $30
The total cost for using 3GB above the limit would be $40 + $30 = $70
b. For using x GB above the limit
He has to pay $10 per each GB above the limit
Thus, the amount to be paid for x GB above the limit would be x * $10 = $10x
So the total amount to be paid would be the base fee plus over the limit fee= $(40 + 10x)