Question

Maria purchased a prepaid phone card for $45.75. Calls cost 5 cents a minute using this card. The credit, C (in dollars), left after x minutes of calls is given by the following function: C(x) = 45.75 - 0.05x. How much credit is left on the card after Maria uses it for 20 minutes of calls?

A. $44.75
B. $43.75
C. $44.25
D. $44.50

Answer 1

After 20 minutes of calls, the credit left on Maria's prepaid phone card is a) $44.75, calculated by the function C(x) = 45.75 - 0.05x.

Step-by-step explanation:

The credit left on the card after Maria uses it for 20 minutes of calls can be calculated using the function C(x) = 45.75 - 0.05x. Substituting 20 for x to represent the 20 minutes of calls gives us C(20) = 45.75 - 0.05×20, which equals 45.75 - 1.00, or $44.75. Therefore, the correct answer is A. $44.75.

To find the credit left on the prepaid phone card, we need to evaluate the function C(x) = 45.75 - 0.05x, where x represents the number of minutes of calls.

Substituting x = 20 into the function, we get:

C(20) = 45.75 - 0.05(20) = 45.75 - 1 = 44.75

Therefore, after using the card for 20 minutes of calls, $44.75 credit will be left on the card. The correct answer is option A.