GRE
Of the marbles selected, the number that will be red
Of the marbles selected, the number that will be black
The number of positive factors of $$2ab^{2}$$
The number of positive factors of $$a^{2}$$ $$b^{3}$$
$$\frac{1}{3^{n}}$$
$$3(\frac{1}{4^{n}})$$
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