Final answer:
The markup for each gallon of juice is $0.50.
Step-by-step explanation:
The markup is the difference between the selling price and the cost price of a product.
In this case, the cost price of the juice is $2.70 per gallon and the selling price is $3.20 per gallon.
To find the markup, subtract the cost price from the selling price: $3.20 - $2.70 = $0.50 per gallon.
Therefore, the markup for each gallon of juice is $0.50.