Martina purchased a prepaid phone card for $15.00. Calls cost 5 cents a minute using this card. The credit, C (in dollars), left on the card after it is used for x minutes of calls is given by the following function.

C (x) = 15.00 - 0.05x

How much credit is left on the card after Martina uses it for 20 minutes of calls?

Question

Mathematics

Deacon Wheeler

22 September, 07:37

Martina purchased a prepaid phone card for $15.00. Calls cost 5 cents a minute using this card. The credit, C (in dollars), left on the card after it is used for x minutes of calls is given by the following function.

C (x) = 15.00 - 0.05x

How much credit is left on the card after Martina uses it for 20 minutes of calls?

+5

Answers (1)

Know the Answer?

Alessandro Davila · Answer 1

The function is

C (x) = 15.00 - 0.05x

C is how many dollars are left after

x minutes.

So if she uses it for 20 minutes, input that into the x.

C (20) = 15.00 - 0.05 (20)

C (20) = 15.00 - 1

C (20) = 14.00

After 20 minutes, there are $14.00 left on the card.