I am not clear why E is the answer...
we have to find P(E)+P(F) + P(EUF), so using Stm1 and Stm 2, we should be able to find.
i.e 0.6 +0.4 + ( 0.6x0.4)...
So, Isn't the answer should be C
I'm not Bunuel but I'm sure I can help
P (A and B) = P(A) * P (B/A). That means the probability of B given that A happens. Now only way that the second term is equal to P(B) is if they are independent events, otherwise the probability will be affected. For instance if you have some balls to pick from and you remove some and don't replace them then successive probabilities will change right? So back to the question, Are they independent events? We just don't know this.
Hope it helps brother
PS. Just as a side note check also Mutually exclusive events in the GMAT Club Math Book just to be clear with those Probability concepts