media service charges $20 for a phone and $30/month for its economy plan. The equation C =30t + 20 decribes the total cost, C of operating a media service phone for t months.
The total cost for two months of srvice is $_______.?
If a customer has oly 90 avilable, how many month of srvice can he recive.
I came up with $60 and three months of service for $90
no, not quite
if C = 30t + 20
when t = 2, C = 2(30)+20 = 80
When C = 90
90 = 30t + 20
70 = 30t
t = 70/30 or 2 1/3
so he could only get 2 months, since 3 months would have cost him $110