A Set Inside a Union

Difficulty: Medium · Topics: Discrete Mathematics, Sets, Venn Diagrams

A, B and C are sets with Csubset Acup B, and

nbig[(Acap B)setminus Cbig]=3

nbig[Csetminus(Acap B)big]=8

n(C)=2· n(Acap B)

What is n(Acap Bcap C)?