Let $X$ be a continuous random variable with density function
$$f(x)=\left\{\begin{array}{cc}{\frac{|x|}{10}} & {\text { for }-2 \leq x \leq 4} \\ {0} & {\text { otherwise }}\end{array}\right.$$
Calculate the expected value of $X .$ Choose one of the following. Source: Society of Actuaries.
$\begin{array}{ll}{\text { (a) } 1 / 5} & {\text { (b) } 3 / 5} \\ {\text { (c) } 1} & {\text { (d) } 28 / 15} \\ {\text { (e) } 12 / 5}\end{array}$