Prove that the total no of subsets of finite set containing n elements is 2n

you can use permutation combination,

no. of subset=no. of ways of selecting element from a n element set

 as there are n elements and each element will have two choices either we should select or leave it,and we have to use all the elements so there will be 2*2*2*2..........n times ways to select elements from a n element set. so no. of subset=2^n