Question

Consider a marshmallow box containing 13 white, 5 orange, and 10 blue marshmallows.

1. We pick randomly one piece. What is the probability that we get
1. A blue marshmallow
2. A white marshmallow 3. An orang marshmallow


2. We pick 2 marshmallows. What is the probability that we get

1.2 marshmallows of the same color
2. at least one red marshmallow

Answer 1

$\text{the probability that we get} \\ \text{1.1. A blue marshmallow} =\frac{10}{28}\\ 1.2.\text{ A white marshmallow}=\frac{13}{28}\\ 1.3. \text{An orang marshmallow} =\frac{5}{28}\\ 2.1. \text{marshmallows of the same color} \\=\frac{10}{28}\times\frac{9}{27}+\frac{13}{28}\times\frac{12}{27}+\frac{5}{28}\times\frac{4}{27}\\ =\frac{266}{756}\\ 2.2. \text{ at least one red marshmallow}=0$