Question

A pair of six-sided dice is rolled one time. What is the probability that the number 5 will appear?

Answer 1

Given that there is a pair of six-sided dice, let be the probability to obtain a 5 in the first dice:

$P_1$

And let be the probability to obtain a 5 in the second dice:

$P_2$

Then, the probability to obtain a 5 in one of the two dices will be equal to:

$P=P_1\cup P_2$

Therefore:

$P=P_1+P_2$

The dice has 6 sides, hence the probability that a 5 appears for each dice is:

$\frac{1}{6}$

Therefore:

$P=\frac{1}{6}+\frac{1}{6}$

Adding the fractions, you get:

$\begin{gathered} P=\frac{2}{6} \\ \\ P=\frac{1}{3} \end{gathered}$

Hence, the answer is:

$P=\frac{1}{3}$