Media Services charge $40 for a phone ad $20/month for its economy plan. The equation c = 20t + 40 describes the total cost, c, of operating a Media Services phone for t months.

The total cost for 3 months of service is $__________

If a customer has only $90 available, how many months of service can she receive?

A. 2

B. 2-1/2

C. 2-1/3

D. 3

90 = 20t + 40

20t = 50

t = 2.5 months

The correct answer is B - 2-1/2