What is the expected return for alpha corporation

Question

Question: Consider the following probability distribution of returns for Alpha Corporation:

Current Stock Price ($)         Stock Price in One Year ($)     Return R    Probability PR

$35                               40%              25%

$25                                                $25                                 0%              50%

$20                              -20%              25%

What is the expected return for Alpha Corporation? What is the variance return on Alpha Corporation? What is the standard deviation of the return on the Alpha Corporation?