Question

What is the probability of picking at least 3 white crayons when you pick 4 crayons from a box with 7 whites and 5 blues?

Answer 1

You can have at least 3 whites if 3 are white and 1 is blue or 4 are white and none are blue when drawing 4 cards:
$$
\large{
P(X\ge3)=\cfrac{\binom{7}{3}\binom{5}{1}}{\binom{12}{4}}+\cfrac{\binom{7}{4}\binom{5}{0}}{\binom{12}{4}}\\
=\cfrac{14}{33}=0.\overline {42}
}
$$
Or about 42.4%

Make sense?

Answer 2

Yes, thanks for the help!

Answer 3

you're welcome