Given:
Number of black marbles = 6
Number of white number marbles = 6
Both marbles have an equal chance of being selected :
[tex]\begin{gathered} P(\text{black marble) = }\frac{Number\text{ of black marble}}{Total\text{ number of marbles}} \\ =\text{ }\frac{6}{12} \\ P(\text{white marble) = }\frac{6}{12} \end{gathered}[/tex]The least number of marbles that must be chosen to be certain that you have chosen 2 white marbles is 8 marbles.
