Find the Expected Value of a Random Variable X Having

Multiple Choice

Find the expected value of a random variable X having the following probability distribution: $$\begin{array} { c c c c c } x & 2 & 4 & 6 & 8 \\P ( X = x ) & \frac { 9 } { 40 } & \frac { 6 } { 40 } & \frac { 1 } { 40 } & \frac { 24 } { 40 }\end{array}$$ Round your answer to tenth if necessary.

A) $E ( X ) = 4$
B) $E ( X ) = 5$
C) $E ( X ) = 6$
D) $E ( X ) = 10$
E) $E ( X ) = 20$