There are 2 possible scenarios, A and B. Scenario A has a 50% chance of being successful. Scenario B has two stages and a 80% chance of being successful at the first stage. If Scenario B is successful at the first stage (B.1), then there is a 100% chance of being successful at B.2.1 and a 50% chance of being successful at B.2.2 (B.2.1 and B.2.1 are not mutually exclusive).
Which scenario should we pick? I am having trouble finding the solution and determining the utilities.