Question

1. A fair six-sided die is rolled. Find the probability of getting at least a 3.

Answer 1

To solve for the probability of atleast a 3:

$\text{probability}=\frac{\text{ number of required outcome}}{\text{ number of possible outcome}}$$\begin{gathered} \text{Number of possible outcome = 6 } \\ \text{ Number of required outcome= 3, 4, 5},6 \end{gathered}$$\begin{gathered} Pr(\text{ atleast a 3) = }\frac{\text{ number of a 3 , a 4 , a 5 , a 6}}{nu\text{mber of possible outcome}} \\ Pr(atleast\text{ a 3) = }\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6} \\ Pr(\text{atleast a 3)=}\frac{4}{6}=\frac{2}{3} \end{gathered}$

Hence the probability of getting at least a 3 = 2/3