Number 9
2 marks · HardA supermarket sells a 950 ml bottle of cooking oil for $4.71. Another supermarket sells a 2.5 litre bottle for $12.15. Work out which bottle is better value for money and give the cost per litre for the better value bottle.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
2.5 litre bottle, $4.86 per litre
Also accept: 2.5L bottle, 4.86; 2.5L, $4.86/L; 2.5 litre, $4.86/litre
Common mistakes: Choosing the 950 ml bottle as better value; Incorrect conversion of ml to litres
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Correctly finds and compares the cost per litre for both bottles.
A1 · 1 mark · Identifies the 2.5L bottle as better value and correctly gives $4.86 per litre (accept $4.86, 4.86 or 4.86/L). (follow-through)
Worked solution
First, convert 950 ml to litres:
Calculate the price per litre for each bottle:
For 950 ml bottle:
For 2.5 litre bottle:
The 2.5 litre bottle is better value for money. Cost per litre is $4.86.