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Number, NAP-C4-CA19

Pamela looks at the price of four sunscreens.
 

 
Which sunscreen is the cheapest per litre?

`text(Sun)` `text(Sport)` `text(Block)` `text(Wet)`
 
 
 
 
Show Answers Only

`text(Sport sunscreen)`

Show Worked Solution

`text(Sun)\ =1090/1200 = 0.91\ text(c/mL)`

STRATEGY: Finding the cost per mL is much more efficient in answering this question than finding the cost per litre.

`text(Sport)\ =540/600 = 0.9\ text(c/mL)`

`text(Block)\ =475/500 = 0.95\ text(c/mL)`

`text(Wet)\ =740/750 = 0.99\ text(c/mL)`

 

`:.\ text(Sport sunscreen is the cheapest per litre.)`

Number, NAP-F3-CA30 SA

A pet store sells its high growth dog food in four different sizes.
 

 
What is the lowest price a customer can pay for 10 kg of high growth dog food?

$   
Show Answers Only

`$44.65`

Show Worked Solution

`text(Calculate the cheapest way to purchase 1 kg:)`

`text(Option 1: C)text(ost)\ = $4.60`

`text(Option 2: C)text(ost)\ =9.10/2 = $4.55`

`text(Option 3: C)text(ost)\ = 13.35/3 = $4.45`

`text(Option 4: C)text(ost)\ =22.50/4 = $4.50`

 `=>\ text(Cheapest option will be to buy three 3 kg bags)`

 `text(and one 1 kg bag.)`

`:.\ text(The lowest price for 10 kg)`

`= 3 xx $13.35 + 1 xx $4.60`

`= $44.65`

Number, NAP-H3-NC18

This table shows the prices of different kinds of nuts sold at a farmers' market.

   

Which one of these are the most expensive nuts per kilogram?

pecans cashews almonds walnuts
 
 
 
 
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`text(Cashews)`

Show Worked Solution

`text(Consider each option:)`

`$1.80\ text(for 250 g = 4 × $1.80 = $7.20 per kg)`

`$6.00\ text(for 750 g = $2 per 250 g = $8 per kg)`

`$7.60\ text(for 1 kg)`

`$3.90\ text(for 500 g = 2 × $3.90 = $7.80 per kg)`

 

`:.\ text(Cashews are the most expensive)`

Number, NAP-I3-CA23

The table below lists the original price and the amount of discount of a pair of jeans at four different shops.
 

 

 
Which shop has the lowest sale price for the jeans?

`text(A)` `text(B)` `text(C)` `text(D)`
 
 
 
 
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`text(Shop B)`

Show Worked Solution

`text(Consider the sale price at each shop:)`

`text(A)` `= 20 – (25text{%} xx 20) = $15`
`text(B)` `= 21 – (1/3 xx 21) = $14`
`text(C)` `= 18 – (20 text{%} xx 18) = $14.40`
`text(D)` `= 17 – 2 = $15`

 

`:.\ text(Shop B has the lowest sale price.)`

Number, NAP-I3-CA19

Nigella needs to buy some olive oil.

The supermarket sells Nigella's favourite oil in a number of different sizes.

Which size costs her the least per mL?

 
 `text(200 mL bottle for $2.50)`
 
 `text(300 mL bottle for $2.50)`
 
 `text(500 mL bottle for $4.50)`
 
 `text(750 mL bottle for $7.50)`
Show Answers Only

`text(300 mL bottle for $2.50)`

Show Worked Solution

`text(Calculate the cost per mL for each option:)`

`text(200 mL for $2.50 = 250/200 = 1.25 c/mL)`

`text(300 mL for $2.50 = 0.83 c/mL)`

`text(500 mL for $4.50 = 0.9 c/mL)`

`text(750 mL for $7.50 = 1 c/mL)`

 

`:. 300\ text(mL bottle for $2.50 costs the least per mL.)`