Q23. - Algebra 2

Question

For Exercise 22 and 23, use the following information.

Sarah has a long-distance telephone plan where she pays 10 cent for each minute or part of a minute that she talks, regardless of the time of day.

23. Sarah made a call to her brother that lasted 9 minutes and 40 seconds. How much did the call cost?

Step-by-Step Solution

Answer

The call cost 100 cents.

Step-1 – Step function.

The graph of a step function contains all constant pieces, and these pieces are observed across the adjacent intervals of the function. Their values change form one interval to another.

Step-2 – Determine the cost function.

It is given that she pays 10 cents for each minute, and she made a call to her brother that lasted 9 minutes and 40 seconds.

Since the call rounds to the next whole number, thus, duration of call is 10 minutes.

Therefore, the call cost function is $f\left(x\right)=10x$

Step-3 – Put the value of x into the cost function.

Put 10 for x into the function $f\left(x\right)=10x$.

$\begin{array}{l}f\left(x\right)=10\left(10\right)\\ f\left(x\right)=100\end{array}$

Thus, the call cost is 100 cents.