Answer:
You should use 0.6 cups of pineapple juice if you only have 1 cup of orange juice.
Step-by-step explanation:
With the information provided about the recipe, you can use a rule of three to find the cups of pineapple you should use if you only have 1 cup of orange juice given that the recipe calls for 30 cups of orange juice and 18 cups of pineapple juice:
30 cups of orange juice → 18 cups of pineapple juice
1 cup of orange juice → x
x=(1*18)/30=0.6 cups of pineapple juice
According to this, the answer is that you should use 0.6 cups of pineapple juice if you only have 1 cup of orange juice.