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Algebra, STD2 A2 SM-Bank 3

The average height, , in centimetres, of a girl between the ages of 6 years and 11 years can be represented by a line with equation

where is the age in years. For this line, the gradient is 6.

  1. What does this indicate about the heights of girls aged 6 to 11?   (1 mark)

  2. Give ONE reason why this equation is not suitable for predicting heights of girls older than 12.   (1 mark)

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i. 


 

ii. 

Algebra, STD2 A2 2009 HSC 24d

A factory makes boots and sandals. In any week

• the total number of pairs of boots and sandals that are made is 200
• the maximum number of pairs of boots made is 120
• the maximum number of pairs of sandals made is 150.

The factory manager has drawn a graph to show the numbers of pairs of boots () and sandals () that can be made.
 

 

  1. Find the equation of the line .   (1 mark)

  2. Explain why this line is only relevant between and for this factory.     (1 mark)

  3. The profit per week, , can be found by using the equation  .

     

    Compare the profits at and .     (2 marks)

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  2.  

     

     

     

Show Worked Solution

i.    

♦♦♦ Mean mark part (i) 14%. 
Using is a less efficient but equally valid method, using    and  (-intercept).

 

ii. 

♦ Mean mark 49%

 

iii. 

♦ Mean mark 40%.