How much root beer and ice cream should you buy to make 100 floats?

- Each float requires about 1/2 cup of root beer.

- 100 floats will require 100 x 1/2 = 50 cups of root beer.

- 1 gallon of root beer contains about 16 cups.

- Therefore, you will need 50 / 16 = 3.125 gallons of root beer.

- It's usually recommended to buy an extra gallon to account for spills, wastage, or extra servings. So, buy 4 gallons of root beer.

Ice cream:

- Each float requires about 2 scoops of ice cream.

- 100 floats will require 2 x 100 = 200 scoops of ice cream.

- 1 gallon of ice cream contains about 16 scoops.

- Therefore, you will need 200 / 16 = 12.5 gallons of ice cream.

- Again, it's advisable to buy an extra gallon for additional servings or possible wastage. So, buy 13-14 gallons of ice cream.