If two sets A and B are having 99 elements in common the number of elements common to each of the sets AxB and Bx A are 121λ2 the value of λ is
n((A×B)∩(B×A))=n((A∩B)×(B∩A)) =n(A∩B)⋅n(B∩A) =n(A∩B)⋅n(A∩B) =99×99=121×92∴ λ=9