Question

13. If n(U) = 20, n(A) = 12, n(B) = 11 and n(A UB)' = 7, find A B​

Answer 1

Answer:

A = 2, B = 1

Step-by-step explanation:

given , n(A) = 12

           n(B) = 11

      n(AUB)' = 7

            n(U) = 20.

n(AUB) = n(U) - n(AUB)'

            = 20 - 7

            = 13.

we know, n(AUB) = n(A) + n(B) - n(AnB)

                        13 = 12 + 11 - n(AnA)

                 n(AnB) = 12 + 11 - 13

                             = 10

therefore, A = n(A) - n(AnB)

                    = 12 - 10

                    = 2

                B = n(B) - n(AnB)

                    =11 - 10

                    = 1