Question

Two fair dice are rolled. What is the probability of getting a sum of $7$?

• A. $1/36$
• B. $1/6$
• C. $7/12$
• D. $5/12$

Answer 1

The correct option is B $1/6$

Let $E$ be the event of getting the sum $7$.

$\therefore E=\left\{\right(1,6),(2,5),(3,4),(4,3),(5,2),(6,1\left)\right\}$

$\Rightarrow n\left(E\right)=6$.

We know $n\left(S\right)=36$ when two fair dice are rolled.

$P\left(E\right)=\frac{n\left(E\right)}{n\left(S\right)}=\frac{6}{36}=\frac{1}{6}$