A stateful expectation of existence is what the denominator describes, but if you forced it to describe people, then you'd phrase it as "how many (ghosts) could possess (any number of apples)?"

Which would be infinite, since ghosts occupy no space and can't interact with physical reality.

As a proportion, compared to nonexistence, any quantity of something is infinitely greater than nothing, so if not n/0, how would you express you expect not the absence of a thing, but its nonexistence?