On T.V. game show, the constestant is aksed to select a dorr 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 dorrs have behind thema 40,000 foreight car, a 3$ silly straw, and a 50$ mathematics textbook.

I thought that I should add all the values together and then would all have a 1/3 chance of being selected. But some what confused on how to put this together.

since it is equal probability you do add all three values and divide by three to get your answer