Two dice are rolled. If a random variable $X$ is defined as the absolute difference of the two numbers that appear on them, then the mean of $X$ is

• A

  0
• B

  $\frac{13}{18}$
• C

  $\frac{19}{9}$
• Correct answer
  D

  $\frac{35}{18}$

Solution

Two dice are rolled $X=$ Absolute difference of two number
$$ \begin{aligned} \mu(\text { Mean })=\Sigma P_i X_i & =\frac{0+10+16+18+16+10}{36} \\ & =\frac{70}{36}=\frac{35}{18} \end{aligned} $$

Hence, the correct answer is option: 'D'.