Question

Haley pays a monthly fee of $20 for her cell phone and then pays 5 cents per minute used. The total cost of Haley’s monthly cell phone bill can be expressed by the function C(m) = 0.05m + 20, where m is the number of minutes used. What are the domain and range of the function C(m)?

Answer 1

The domain is
`D_C = [0,\infty)`

The range is:
`R_C = [20,\infty)`

Explanation:

Domain and range of a function:

The domain of a function are the values that the input assumes, while the range are the values that the output assumes.

In this question:

`C(m) = 0.05m + 20`

m is the input, which is the number of phone calls, which can be any number between 0 and infinite. So

The domain is
`D_C = [0,\infty)`

When the input is m = 0, the value of C(0) = 20. As m increases, so does C(m). This means that:

The range is:
`R_C = [20,\infty)`

Answer 2

Option 1 because

domain: m is Greater than or equal to zero

range: C is greater than or equal to twenty

Explanation:

The (C) cost of the bill is always going to start at twenty and be higher depending on how many (m) minutes were used.

Edg2021