The cell phone plan from Company C costs $10 per month, plus $15 per gigabyte for data used. The plan from Company D costs $80 per month, with unlimited data. Rule C gives the monthly cost, in dollars, of using gigabytes of data on Company C’s plan. Rule D gives the monthly cost, in dollars, of using gigabytes of data on Company D’s plan.
A. Which is less, C(4)or D(4)? What does this mean for the two phone plans?
B. Which is less, C(5)or D(5)? Explain how you know.

ANSWER-

C(g) = 10 + 15g

C'(g) = 80

The monthly charges of Company C for using 2 Gigabyte of data usage.

Step-by-step explanation:

The cell phone plan from Company C costs $10 per month, plus $15 per gigabyte for data used. The plan from Company D costs $80 per month, with unlimited data.

Now, the monthly cost in Company C for using g gigabyte of data will be  

C(g) = 10 + 15g (1)

Again, the monthly cost in Company D for using g gigabyte of data will be  

C'(g) = 80 (2)

Now, from equation (1), the statement C(2) = 10 + 15 × 2 = 40, means that monthly charges of Company C for using 2 Gigabyte of data usage. (Answer)