Assessment Problem:

Phone Cost Problem

The Jog Phone Company is currently offering a calling plan that charges 10¢ per minute for the first 5 minutes for any phone call. Any additional minutes cost only 6¢ per minute.

1. How much would a 3-minute phone call cost? An 8-minute phone call? A 15-minute phone call? Explain how you determined these.

2. How much would a 123-minute phone call cost? Explain how you determined this.

3. Suppose that a certain phone call (using the Jog Company plan) costs $4.64. How many minutes long was the call? Explain how you determined this.

4. Explain how you would determine the cost for any number of minutes under this plan. Write a formula to explain how you would determine this cost.

Domain:

Patterns & Functions

Theme:

Modeling

Common Core Standards:

A-CED.2

Research References:

Lannin, J. K., Barker, D. D., & Townsend, B. E. (2006).