suppose A1, A2, ,A30 are 30 sets each with 5 elements and B1, B2, - Maths - Sets

Question

suppose A1, A2, ,A30 are 30
sets each with 5 elements and B1, B2, ,
Bn are n sets each with 3 elements let union
ofA1, A2, ,A30 = union
ofB1, B2, , Bn =S Each element of
S belongs to 10 of A's and 9 of B's find n
WHAT DOES IT MEAN????????????

Vipin Verma · Accepted Answer

Since each Ai has 5 elements and each element of S belong to exactly ten of Ai 'sHence S = ∪30i = 1 Ai ⇒n(S) =110∑i=130n(Ai) =110×5×30 =15And each of Bj has three element and  each of S belongs to exactly 9  of Bj'sHence S= ∪nj= 1  Bj  ⇒n(S) =19∑j=1nn(Bj) =193n =n3And both n(S) are equal So n3 =15 Or n = 45

suppose A1, A2,....,A30 are 30 sets each with 5 elements and B1, B2,...., Bn are n sets each with 3 elements. let union ofA1, A2,....,A30 = union ofB1, B2,...., Bn =S. Each element of S belongs to 10 of A's and 9 of B's. find n. WHAT DOES IT MEAN????????????

suppose A₁, A₂,....,A₃₀ are 30 sets each with 5 elements and B₁, B₂,...., B_n are n sets each with 3 elements. let union ofA₁, A₂,....,A₃₀ = union ofB₁, B₂,...., B_n =S. Each element of S belongs to 10 of A's and 9 of B's. find n.

WHAT DOES IT MEAN????????????