So I have a question that is probably easy for many people to solve, however I cannot quite figure it out. I am trying to calculate the ABV (Alcohol by Volume) in a mixed drink recipe that I am making for the holidays. So here it goes....

I have two gallons of apple juice to which I am adding a 750 ML bottle of alcohol which is 75.5% alcohol, after adding the alcohol to the total batch what is my new ABV?

The farthest along in the math I can make it is that 750 ML is approximately 20% of one gallon or 10% of the total batch, Am I correct, and directions on how to solve this would be much appreciated! Thanks in advance!