Suppose A1, A2,....................., A30 are thirty sets each having 5 elements each and B1, B2,................Bn are n sets each with 3 elements each. Let 30⋃i=1Ai=n⋃j=1Bj=S and each element of S belongs to exactly 10 of Ai's and exactly 9 of the Bj's. Then n is equal to

Suppose A1, A2,....................., A30 are thirty sets each having

1.	Suppose A1, A2,....................., A30 are thirty sets each having 5 elements each and B1, B2,................Bn are n sets each with 3 elements each. Let 30⋃i=1Ai=n⋃j=1Bj=S and each element of S belongs to exactly 10 of Ai's and exactly 9 of the Bj's. Then n is equal to
Answer» Suppose $A_{1}, A_{2}, . . . . . . . . . . . . . . . . . . . . ., A_{30}$ are thirty sets each having 5 elements each and $B_{1}, B_{2}, . . . . . . . . . . . . . . . . B_{n}$ are $n$ sets each with 3 elements each. Let $30 ⋃ i = 1 A_{i} = n ⋃ j = 1 B_{j} = S$ and each element of $S$ belongs to exactly 10 of $A_{i}$ 's and exactly 9 of the $B_{j}$ 's. Then $n$ is equal to