To equal 1 gallon of wine it takes 5 bottles of wine.
5 bottles of wine equal 1 gallon of wine.
There are 128 ounces in 1 gallon.
A bottle of wine is 25.4 ounces in size so it would take 5 of those bottles of wine to make 1 gallon of wine.
That goes for other liquid as there is always 128 ounces of liquid in 1 gallon.
So to find out how many bottles of the liquid such as the wine it would take to make a gallon take the number of bottles and multiply them until you get 128.
There would be 10 bottles of wine in 2 gallons and 15 bottles of wine in 3 gallons and 20 bottles of wine in 4 gallons and 25 bottles of wine in 5 gallons.