Suppose a,, az, a , ago are thirty sets each having 5 elements and b,, b, b b are n sets 30 each with 3 elements. let ja, =ub, = s and each elements of s belong

Suppose A,, Az, A , Ago are thirty sets each having 5 elements and B,, B, B B are n sets 30 each with 3 elements. Let JA, =UB, = S and each elements of S belongs to exactly 10 of the j=1 i=1 A, S and exactly 9 of the B, S. Then, n is equal to-