A refrigerator has the shape of a recgtangular prism. The volume of a rectangular prims is:

Use the formula above and the given dimenssions to find the volumen of the refrigerator:

Substract the volume take by the walls and other parts of the refrigerator from the total volume to find how many cubic feet are left for food:

Then, there are 25 cubic feet left for the food in the refrigerator