Final answer:
The ratio of Granny Smith apples to Gala apples is 3 to 5.
Step-by-step explanation:
To find the ratio of Granny Smith apples to Gala apples, we need to divide the number of Granny Smith apples by the number of Gala apples.
The number of Granny Smith apples is 18.
The number of Gala apples is 30.
Therefore, the ratio of Granny Smith apples to Gala apples is 18 to 30, which can be simplified to 3 to 5.