The shaded portion in the venn diagram above represents?

If n(P) = 20 and n(Q) = 30 and n(PuQ) = 40, find the value n(PnQ)

Given that A and B are sets such that n(A) = 8, n(B)=12 and n(AnB) =3, find n(AuB).

A local community has two newspapers: the morning tomes and the evening dispatch. The morning times is read by 45% of the households.  The Evening Dispatch is read by 60% of the households.  Twenty percent of the households read both papers.  What is the probability that a particular household reads at least one paper?