Answer: They are the same equivalent price, $0.95/liter.
Step-by-step explanation:
Choices: $3.58 per gallon, or $3.79 for 4 L.
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We need to convert one of the volumes. I'll convert gallons to liters.
By definition, 1 gallon = 3.785 liters
Make this into a conversion factor:
We can make it either:
1) (3.785 liters/gallon), or
2) (1 gallon/3.785 liters)
Now convert the $3.58/gallon into dollars/liter. We'll use the second conversion factor so that gallons cancels out when we multiply:
($3.58/gallon)*(1 gallon/3.785 liters) = $0.95/liter.
The grocery store milk must also be converted to a price expressed per 1 liter:
$3.79 for 4 L
= $0.95/liter.
They are the same equivalent price, $0.95/liter.