I need help

On a TV game show, the contestant is asked to select a
door and then is rewarded with the prize behind the door
selected. If the doors can be selected with equal probability,
what is the expected value of the selection if the
three doors have behind them a $40,000 foreign car, a $3
silly straw, and a $50 mathematics textbook?

Every time.

\(\displaystyle \sum x\cdot p(x)\)

40000(1/3) + 3(1/3) + ... You're not going to make me do all the work, are you?