Question

A telephone company offers a monthly cellular phone plan for $ 19.99. It includes 350 anytime minutes plus $ 0.20 per minute for additional minutes. The following function is used to compute the monthly cost for a​ subscriber, where x is the number of anytime minutes used.

C(x)= 19.99 if 0 < x ≤ 350
0.20x-50.01 if x > 350

Compute the monthly cost of the cellular phone for use of the following anytime minutes.

a. 215

b. 385

c. 351

Answer 1

Answer:

(a) $19.90 (b) $26.90 (c) $20.10

Step-by-step explanation:

C(x) = $19.90 for 0 < x ≤ 350

C(x) = $19.90 + $0.20x for x > 350

a) Total number of minutes = 215

215 mins is less than 250 mins

Therefore the cost is $19.90

b) Total number of minutes = 385

385 mins is greater than 350 mins

It is (385 - 350) = 35 mins more than 350 mins

Therefore the cost is $19.90 + $0.20(35) = $26.90

c) Total number of minutes = 351

351 is greater than 350 mins

It is (351 - 350) = 1 min more than 350 mins

Therefore the cost is $19.90 + $0.20(1) = $20.10

Answer: (a) $19.90 (b) $26.90 (c) $20.10