A telephone company offers a monthly cellular phone plan for $\$ 34.99$. It includes 300 anytime minutes plus $\$ 0.25$ per minute for additional minutes. The following function is used to compute the monthly cost for a subscriber, where $\mathrm{x}$ is the number of anytime minutes used.
\[
C(x)=\left\{\begin{array}{ll}
34.99 & \text { if } 0300
\end{array}\right.
\]
Compute the monthly cost of the cellular phone for use of the following anytime minutes.
(a) 195
(b) 335
(c) 301
Solution
Step 1 ：The problem provides a function to calculate the monthly cost of a cellular phone plan. The function is defined as follows: \[C(x)=\left\{\begin{array}{ll} 34.99 & \text { if } 0
Step 2 ：We are asked to calculate the monthly cost for three different scenarios: (a) 195 minutes, (b) 335 minutes, and (c) 301 minutes.
Step 3 ：For (a), since 195 is less than or equal to 300, we use the first part of the function. So, the cost is \$34.99.
Step 4 ：For (b), since 335 is greater than 300, we use the second part of the function. So, the cost is \(0.25 \times 335 - 40.01 = \$43.74\).
Step 5 ：For (c), since 301 is greater than 300, we use the second part of the function. So, the cost is \(0.25 \times 301 - 40.01 = \$35.24\).
Step 6 ：Final Answer: The monthly cost of the cellular phone for use of 195 minutes is \(\boxed{34.99}\) dollars, for 335 minutes is \(\boxed{43.74}\) dollars, and for 301 minutes is \(\boxed{35.24}\) dollars.
