Computer discounts

Computer discounts

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about working out percentages.

 

EdTEK Computers buy computers at a special price from BIM (a large computer manufacturer).
 
a)   The price of a BIM computer is $3000.00 but EdTEK buys them for 60% of this price.
 
      What price does EdTEK pay for a computer? $__________

   

b)   EdTEK pays $500.00 for each printer and adds 30% onto this price when they sell it.
 
      What price does EdTEK sell each printer for? $__________
 
c)   A new computer is sold for $3000.00. Every six months the value of the computer decreases by 20%.
     What is the value of the computer
 
      i)    after six months? $__________
 
      ii)   after one year? $__________
 
d)   Jen bought a computer from EdTEK for $2400.00 and sold it a year later for $1632.00.
 
      What was Jen's loss written as a percentage? __________ %
 
e)   EdTEK buys joysticks from BIM for $50.00 and sells them for $62.95.
 
      What is EdTEK's profit written as a percentage? __________ %
Task administration: 
This task is completed with pencil and paper only.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
percentages, money, discount
Description of task: 
Students increase and decrease quantities by given percentages.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Multiplicative thinking, sets 8-9
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y10 (09/1999)
a)   1800 easy
b)   650 moderate
c) i)
ii)		 2400
1920 [Accept d) i) × .8]		 difficult
very difficult
d)   32 difficult
e)   25.9 very difficult
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
a) 1200 3000 - 3000 × 0.6 Calculates amount of price reduction.
b) 150 500 × .3 Calculates the amount of price markup.
d) 68 × 100 Calculates percentage of original price rather than percentage loss.
e) 12.95 62.95 - 50 Calculates the amount of profit rather than percentage of profit.