I'm stuck in this question, could someone give me a hand? I'll post what I've done so far.
Question 9: Let $A=(1,2,3,4)$ and $Z=(1,2,3,4,5,6,7,8,9,10)$, if a subset B of Z is selected by chance calculate the probability of:
a) $P(B⊂A)$ B is a proper subset of A
$(3/10)*(2/10)*(1/10) =3/500$ of chance
b)$P(A∩B=Ø)$ A intersection B =empty set
Is it correct?