Answer:
15 servings
Explanation:
total amount of lemonade = 19.64 cups
lemonade per serving = 1.25 cups
total servings = 19.64 cups / 1 .25 cups = 15.712 servings
since you cannot sell a partially full serving, Jessica and Jonathan will only be able to sell 15 servings
in order for them to sell 16 full servings, they need to prepare 20 cups of lemonade (= 20 / 1.25 = 16)