Question

A cell phone company charges $300 for a new phone and $40 for a monthly plan. If C (t) is a rational function that represents the average monthly cost of owning the cell phone, what is the range of the function?

R: ℝ
R: (0, 300)
R: (40, 340)
R: (–∞, ∞)

Answer 1

The $300 charge will last until the new phone is paid off. After that the monthly charge will be $40 only.

The range of the function will be between $40 and $340:

• R:[40, 340]

Correct choice is C

Answer 2

• Charge for new phone =$300
• Charge per month as monthly plan=$40

Now

`\\ \rm\hookrightarrow \mathbb{R}=(x,y)`

`\\ \rm\hookrightarrow \mathbb{R}=(40,300)`