Hi to everybody.

I cannot follow this reasoning.

Why does Greg state that the probability is the same? It’s stated that there is NO REPLACEMENT, so i thought that:

A: When you remove the third marble, your probability depends on which colours were removed before, and the marbles left in the bag are 3.

B: When you remove the fourth marble, your probability is dependent of which colours were removed before, and it the marble left in the bag is just 2.

B can be 0, or 1 or 0.5, and A can also have different probabilities.

Why does he state that is C and not D?

Whats wrong with my reasoning?

Thanks guyss!