Answer: Option B is the cheaper deal (the 12 batteries for $14.76)
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Explanation:
For the first deal we can say
3 batteries = 4.80 dollars
3/3 batteries = 4.80/3 dollars .... divide both sides by 3
1 battery = 1.60 dollars
The unit price for the first deal is $1.60 per battery.
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For the second deal we could say
12 batteries = 14.76 dollars
12/12 batteries = 14.76/12 dollars .... divide both sides by 12
1 battery = 1.23 dollars
The unit price for the first deal is $1.23 per battery.
This is the cheaper deal.
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So in short, you're dividing the total cost over the number of items to get the unit price.
