1. Sketch your examples, labeling both axesZ
Learning Objective
To be able to construct linear graphs arising from real life problems
To be able to discuss and interpret graphs modeling real situations
Cell Phone Data?
Working in your teams discuss what data about mobile
phones could be represented on a straight line graph
You need to identify two specific examples
Sketch your examples, labeling both axes

2. Pay as you Go Cell Phones: Independent WorkZ
Pay as you Go Cell Phones: Independent Work
Working independently, work through the instructions on the sheet
When instructed, discuss your answer for step 4 with your team
Help your team mates to complete their sheets

3. Pay as you Go Cell Phones: Team WorkZ
Pay as you Go Cell Phones: Team Work
Discuss the questions on the sheet in your teams
Ensure you all complete your own sheet with your agreed answers
Create your own question based on the data provided

4. Pay as you Go Cell Phones 1
Straight Line Graphs
Pay as you Go Cell Phones 1
Name:
Step 1: Complete the four tables on sheet 2 for the following Pay as you Go Cell Phone deals:
Phone is $50
Calls 35cents per min
Phone is $45
Calls 40cents per min
Phone is $60
Calls 30cents per min
Phone is $80
Calls 10cents per min
Step 2: Using the values in your tables, plot each of the Cell Phone deals on the graph on sheet 2, take care to ensure you plot the points and draw the lines accurately (use a different colored pencil for each line). Ensure your lines and axes are labeled correctly.
Step 3: Write down the equation of the line (in the form y = mx + c) for each of the Cell phone deals:
O2:
Virgin:
T-mobile: 3:
Step 4: Explain below why it is important to identify the number of calls you are likely to make before selecting a Pay as you Go Cell phone deal. Use examples to illustrate your point.

5. Pay as you Go Mobile Phones 3
Straight Line Graphs
Pay as you Go Mobile Phones 3
Name:
Discuss the answers to the following questions in your team, then write down your own answers.
1. How many minutes of calls do you need to make for the 3 phone to be the cheapest deal?
2. Jane estimates that she will make 7 minutes of calls per month over a year.
a. Based on your graph, what phone deal would you recommend she purchases?
b. How much will this cost her?
c. If she chose an alternative provider, what is the most it could cost her? Who is this
with?
d. Calculate your answers to b and c using the relevant equations:
3. Hiresh needs a phone for 6 months and he estimates that he will make between 90 and 130 minutes of calls in that time. What phone deal would you recommend he purchases and why? Provide examples of call costs in your answer.
4. Grandpa Bob wants to buy his first mobile phone, he has $200 in total to spend on the phone and calls over 2 years. What is the maximum number of calls he can make? Which provider is this with? Show your working.

6. Calls (min) 50
100
200
250
Cost ($)
Calls (min) 50
100
200
250
Cost ($) 2 Z
Calls (min) 50
100
200
250
Cost ($)
Calls (min) 50
100
200
250
Cost ($)
150
100 50 50
100
150
200
250

7. Cost ($) No. of Minutes 2 150 100 50 50 100 150 200 250 Z Calls (min)50
100
200
250
Cost ($)
67.5 85
120
137.5
Calls (min) 50
100
200
250
Cost ($) 45 65 85
125
145 2
Calls (min) 50
100
200
250
Cost ($) 60 75 90
120
135
Calls (min) 50
100
200
250
Cost ($) 80 85 90
105
150
Virgin O2
T-mobile 3
100
Cost
($) 50 50
100
150
200
250
No. of Minutes