1. You might want to retry asking the question. It is unclear, and seems incomplete.

    However, when you're dealing with 3 sets, the following formulae might come in handy. 

    n (A U B U C) = n(A) + n(B) + n(C) - n(A ∩ B) - n(A ∩ C) - n(B ∩ C) + n(A ∩ B ∩ C)

    n(U) = n (A U B U C) + n (A U B U C)c

    where, A, B and C are three non-empty sets, 
    U denotes the Universal Set

    and c (in superscript) indicates complement of a set (Complement of a set: is the difference of a set from the Universal set)

  2. Let N and B denote the set of people whi can speak Newari and Bhojpuri reapectively.

    Now, n(U)=200, n(N)=150, n(B)=80 and (A∩ B)' = 30 

    i) Let (A∩ B) = x

    Representing above information in a venn diagram.

    From the venn diagram,

    150-x + x +80-x + 30=200

    Or,  260-x = 200

    Or, x= 260-200

    Therefore, x=60.

    ii) n(N∪B) = n(N)+ n(B) - n(N∩B)

                       = 150 + 80 - 60

                       = 170

    iii) n०(N)+ n०(B)= 150-x + 80-x

                                 = 150-60+80-60

                                 = 110


    No.of people speaking both language=60

    No.of people speaking at least one language= 170

    No.of people speaking only one language= 110

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