Linear Relationships, SM-Bank 022

Sabre is saving to buy a new skateboard.

After one week she has saved $11.

She then saves the same amount of money each week.

Week	1	2	3	4
Total Amount Saved	$11	$18	$25	$32

State the rule linking the week and the total amount saved. (2 marks)

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How much money will Sabre have saved by the end of week 10? (2 marks)

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Show Answers Only

a. $\text{Rule: Amount saved}=$4 + \text{week}\times 7$

b. $$74$

Show Worked Solution

a. $\text{Total at end of week }1= $11$

$\therefore\ \text{After week 1 savings increase by }$7\ \text{per week}$

$\therefore\ \text{Total at end of week 2}=$4 + 2\times 7= $18$

$\therefore\ \text{Total at end of week 3}=$4 + 3\times 7= $25$

$\therefore\ \text{Total at end of week 4}=$4 + 4\times 7= $32$

$\therefore\ \text{Rule: Amount saved}=$4 + \text{week}\times 7$

b. $\text{Total savings at end of week}\ 10$

$= 4 + 10\times 7$

$= $74$