Cost of communication

Cost of communication

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about interpreting a line graph
The graph below shows the setting-up costs for three different types of communication links.
 
Costs over distance of different types of Communication links
graph showing costs of 3 different communication links: radio, copper wire and fibre optic cable

Question

a)  Which would be the most expensive link to use for a distance of 2 km?

    • Radio link

    • Copper cable link

    • Fibre optic cable link

Question 1Change answer

b)  How much would it cost to set up a radio link for 1.5 km? $

Question 2Change answer

c)  Estimate what it would cost to set up a fibre optic link over a distance of 1 km. $

Question 3Change answer

d)  Up to what distance is it cheaper to use copper cable links rather than radio links?  km

Question 4Change answer

e)  Make a general statement comparing the cost of fibre optic and copper cable links.
Task administration: 
This task is completed with pencil and paper or online with some auto-marking.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Patterns and relationships
Keywords: 
graph interpretation, breakeven points, linear equations, simultaneous equations
Description of task: 
Students interpret a line graph of a practical situation.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Using symbols and expressions to think mathematically, sets 6-7
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y10 (10/1998)
a) Fibre optic cable. very easy
b) 40 000 easy
c) 78 000 [Accept in range $75 000-$80 000]. easy
d) Accept answer between 0.55-0.70. moderate
e) For any 1 of:

  • Fibre optic cables are always more expensive than copper (or copper are always cheaper than fibre optic).
  • Fibre optic cables are about $12 000 (range $12 000-$20 000) more than copper cables.
  • Fibre optic cable increases in price faster than copper cable link.
  • Other acceptable answers.
 easy
Diagnostic and formative information: 
  Student response Likely calculation
b)
c)		 40
80		 Ignores ($'000s) on y-axis label.
d) .5 Inaccurate reading of x-axis.