A supermarket sells the same brand of breakfast cereal in two different box sizes, shown in the diagram below, and a shopper wants to know which box is the ...
Question 1 Report
A supermarket sells the same brand of breakfast cereal in two different box sizes, shown in the diagram below, and a shopper wants to know which box is the better buy.
Which box gives better value for money? You must show your working to justify your answer. (3)
Answer Details
To find the better buy between two differently sized packs, both prices are converted to a common unit rate, here pence per 100 g, so the two boxes can be compared fairly.
Box A: £2.20 for 500 g is 220 pence for 500 g:
\[ \frac{220}{500} \times 100 = 44 \text{ pence per 100 g} \]Box B: £3.15 for 750 g is 315 pence for 750 g:
\[ \frac{315}{750} \times 100 = 42 \text{ pence per 100 g} \]Since 42p per 100 g is less than 44p per 100 g, Box B gives the better value for money. [3]
Comparing unit prices this way avoids being misled by the larger total price of Box B: although £3.15 is more than £2.20, Box B is actually the cheaper option once the different weights are taken into account.
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