1. 2.1.1 Calling Plans day 4 calling cards Unit 2: Linear Relationships SWBAT: Compare calling plans by using graphs, tables, and equations

2. Calling Cards Compare the costs associated with pre-paid calling cards offered by two companies. Company A sells a $40 calling card and deducts 16 cents from the balance of the card for each minute used. Company B sells a $30 calling card. The table below shows the balance remaining on the card after different amounts of usage. Minutes Used102550120 Balance Remaining (dollars)$27.60$24.00$18.00$1.20

3. 1.Construct a graph to represent the balance remaining on each calling card over time. Be sure to label each graph.

4. 2. What is the cost per minute for Company B’s calling card? Explain how you found your answer. 3. Describe how the balance for each calling card changes over time. Explain how you can see this on the graph and in the table. 4. How do you know that the relationship between the balance remaining and the number of minutes used is a linear function?

5. 5. What is the initial balance on the calling card for Company A? What is the charge per minute? Use this information to write the equation representing the relationship between the balance remaining and the number of minutes used for Company A. 6. What is the initial balance on the calling card for Company B? What is the charge per minute? Use this information to write the equation representing the relationship between the balance remaining and the number of minutes used for Company B. 7. graph the lines. 8. Company C sells a $24 calling card and deducts 12 cents from the balance of the card for each minute used. Write an equation representing this relationship. Graph all three lines.

6. 9. Which lines intersect? Examine your table of values in the calculator to determine where these lines intersect. Are any of the lines parallel? 10. For each of the three lines, tell where the line hits the x-axis. For each line, use the graph and/or the table of values to help you determine your answer. What is the meaning of these particular points in connection to the problem situation? 11.Which plan is the best buy?