To solve this problem, start by identifying how much the Greenbaums spent over the period of three months.
This is:
$11.85
Since the family was credited $5 each month, you need to add that to their payment to find the regular cost without credit.
To do this, multiply the credit amount by the number of months to find the total price for three months of regular service.
This results in:
5 x 3 = 15
So, to find the total amount for three months of regular service, add the credit price to their paid price.
This results in:
11.85 + 15 = 26.85
So now we know that three months of regular service costs $26.85.
To find the amount it costs for one month we must divide our total amount by the number of months, which is three.
This gives you:
8.95
So the cost for one month of regular service is $8.95.