I think I have part of it figured out. They are all equally 1/5 or .20

1. Pa = e1 + e2 = .2 + .2 = .4

Pb = e3 + e4 = .2 + .2 = .4

Pc = e2 + e3 + e4 = .6

2. P(AUB) = .4+.4 = .8, mutually exclusive

However, there is an additional problem I don't understand.

3. (AUBc) and P(AUBc)

Anyone understand part 3?