Mark the correct alternative in the following:

Suppose A1, A2,...,A30 are thirty sets each having 5 elements and B1, B2,...,Bn are n sets each with 3 elements, let and each element of S belongs to exactly 10 of the and exactly 9 of the , then n is equal to


If elements are not repeated then number of elements in A1A2A3….A30=30*5=150


But, each element of S is in 10 of



If elements are not repeated then number of elements in B1B2B3….Bn=3*n


But, each element of S is in of




3× n=15× 9


n=45

1