Find the Expected Value of a Random Variable X Having

Short Answer

Find the expected value of a random variable X having the following probability distribution: $$\begin{array} { c c c c c } x & 10 & 20 & 30 & 40 \\P ( X = x ) & \frac { 25 } { 60 } & \frac { 20 } { 60 } & \frac { 5 } { 60 } & \frac { 10 } { 60 }\end{array}$$ ​ $$E ( X ) =$$ __________