GRE
n
33
The number of ordered triples ($$x_1$$, $$x_2$$, $$x_3$$), where $$x_1$$, $$x_2$$ and $$x_3$$ are non-negative integers such that $$x_1$$+$$x_2$$+$$x_3=9$$
$$55$$
Of the marbles selected, the number that will be red
Of the marbles selected, the number that will be black
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