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WELCOME TO THIS PAGE INTENDED FOR STUDENTS AT THE UNIVERSITY OF THE WESTERN CAPE REGISTERED IN 2010  FOR THE MODULE:

    QSF  132

W7 L2

PERCENTAGES

                             NOTION (DEF)  -------------PROBLEMS                            

                                      % INCREASE/DECREASE

Text Box: Once you have achieved a basic idea of what percentages are about, you have to master a few important and critical principles (or rules) when dealing with problems relating to percentages.
 Refer to the basic examples on percentage increase and decrease given on pp.103-105* in your COURSE READER.
 Now attempt the following ADDITIONAL problems (WHICH ARE ALSO MORE DIFFICULT or which require a higher level of thinking). Note that these problems are similar to examples 5 and 8, p. 104,  in your Course Reader.
The new petrol price became R7.69 per liter, after an increase of 6.5%. What was the petrol price before this increase? (APPLY RULE 1)
The R/$ exchange rate changed from R7.32/$ to R7.23/$. What is the percentage strengthening of the rand against the US dollar? (APPLY RULE 2)
IS THE QUESTION CLEAR?
WHAT ARE YOU GIVEN?
WHAT ARE YOU ASKED?
HOW DO YOU SOLVE IT?
HOW DO YOU KNOW YOUR ANSWER IS CORRECT?
ACTIVITY : SELF-EXPLORATIONS : DIFFERENT SOLUTIONS

 
 
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THE PRINCIPLES or RULES  

 

RULE 1       BASIS OF ARGUMENT : WHICH IS 100% (OLD OR NEW)

                   WHAT PERCENTAGE DOES THE NEW PRICE REPRESENT?

 

RULE 2       EXPRESS THE DIFFERENCE AS A PERCENTAGE OF THE

                    FIRST (OLD) VALUE.

 

*

PROBLEM

SOLUTION

Increase R400 by 7 %

METHOD 1:  = R30

                  R400 + R30 = R430

METHOD 2:  = R430

Note that  and

Increase R2 by 150%

 

 

 

Decrease R650 by 8%

 = R598

(Use your calculator to simplify)

 

FOR DISCUSSION:

 

On p.44 in the course reader we state: "All (that) the business-minded person seems to be interested in, is the accurate answer, in order to make decisions based on that. Time and answers are of the essence

 

                  

  DESMOND DESAI, DMD EDU-HOME, 2010

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