I have a problem here that I am trying to solve. Event A may take place either due to E1 or E2. The probability of E1 happening is .3, whereas the probability of E2 happening is .2. Also, the likelihood of E2 happening is increased to .3 if E1 occurs. I need to calculate the probability that A happens. I made a tree diagram and calculated the probability, but it doesn't tally with the answer I got from using the formula that relates union and intersection of probabilities.
I really appreciate any help you can provide.enter image description here
