The formula for the probability of the union of two events E and F is \( P(E \cup F) = P(E) + P(F) - P(E \cap F) \). Substituting the given values, we get \( 0.4 = 0.1 + 0.3 - P(E \cap F) \), which simplifies to \( P(E \cap F) = 0 \). The conditional probability of F given E is calculated as \( P(F \,|\, E) = \frac{P(E \cap F)}{P(E)} = \frac{0}{0.1} = 0 \).
Final Answer: \( \boxed{0} \)