If AAA and BBB are sets such that n(AΔB)=10n(A \Delta B) = 10n(AΔB)=10 and n(A∩B)=3n(A \cap B) = 3n(A∩B)=3, and n(A)=7n(A) = 7n(A)=7, what is n(B)n(B)n(B)?
6
9
10
13