Find the number of cubes selected before others

Question

The land of math contains 52 cubes, 46 spheres, 2 oblongs. Question: Suppose that shapes are selected from LOM at random without replacement, until a single sphere is selected. Let $X$ denote the number of cubes selected before a single sphere is selected, derive the probability function $f(x) = P(X = x)$.

This seems like negative hypergeometric?

So we want $\binom{52}{x}$ somewhere, what about the oblongs though?

Answer 1

Hint: When you select an oblong, the number of cubes you have selected does not change. So what does that mean for how the inclusion of oblongs affects the probability function?