Suppose a company is deciding whether to invest in a project. It has a choice of choosing:

1. Project A which produces $350 revenue with certainty

2. Project B which produces $600 revenue with 1/2 probability and $0 with 1/2 probability

The expected value for project B is

A)$950

B)$300

C)$350

D)$4

I know the answer is 4$ but how do you get it.