Let A be any finite set having n elements i.e. A={a1,a2,a3.....ar,ar+1,ar+2..........an-2,an-1,an}
{where 1 is less than or equal to r and r is less than or equal to n]


Q1. how many subsets of set A are there which will not contain any element from a1 to ar ??

Q2. how many subsets of set A are there which must contain each element from a1 to ar ??

Q3.how many subsets of set A are there which will not contain atleast 1 element from a1 to ar ??

Q4.how many subsets of set A are there which will contain atmost one element from a1 to ar ??



FRIENDS PLEASE EXPLAIN ME, I NEED IT....