已知 p(A)=0.4，p(B)=0.3，p(A cup B)=0.5，则 p(A-B)= [填空1] ；p(B-A)= [填空2] 。A-B = A cup B - Bp(A-B) = p((A cup B)-B)= p(A cup B) - p(B) = 0.2

已知 $P(A) = 0.4$，$P(B) = 0.3$，$P(A \cup B) = 0.5$，利用并集公式求交集概率：
$P(A \cap B) = P(A) + P(B) - P(A \cup B) = 0.4 + 0.3 - 0.5 = 0.2$
计算 $P(A - B)$ 和 $P(B - A)$：
$P(A - B) = P(A) - P(A \cap B) = 0.4 - 0.2 = 0.2$
$P(B - A) = P(B) - P(A \cap B) = 0.3 - 0.2 = 0.1$
或者，利用 $A - B = (A \cup B) - B$ 和 $B - A = (A \cup B) - A$：
$P(A - B) = P(A \cup B) - P(B) = 0.5 - 0.3 = 0.2$
$P(B - A) = P(A \cup B) - P(A) = 0.5 - 0.4 = 0.1$
答案：
$P(A - B) = \boxed{0.2}$，$P(B - A) = \boxed{0.1}$