Media service charges $20 for a phone and $30/month for its economy plan. The equation c=30t +20 describes the total cost,c, of operating Media Services phone for t months.
The total cost for 4 months of service is $140?
If a customer has only $90 available, how many months of service can she receive?
A. 2
B. 2 1/3
c. 2 1/2
d. 3
I was thinking C.?
The answer would be B (2 1/3) if the phone company billed for partial months or refunded the unused part of a month. But that is not how most of them work. If payment must be in whole months, the answer would be A.
To find the number of months of service a customer can receive with a given amount of money, you need to solve the equation c = 30t + 20 for t (number of months), where c is the total cost.
Given that a customer has $90 available, you can substitute c = 90 into the equation and solve for t:
90 = 30t + 20
Subtracting 20 from both sides:
90 - 20 = 30t
70 = 30t
Dividing both sides by 30:
70/30 = t
t ≈ 2.33
So, the customer can receive approximately 2.33 months of service. Rounding to the nearest option, the answer is B. 2 1/3.