If A = {1,2,3,4,5}, then the number of proper subsets of A is-
ক
120
খ
30
গ
31
ঘ
32
সঠিক উত্তর: 31
Proper subsets must contain atleast one less element than the elements of the main set. If the number of elements of set A is n, the number of proper subsets of that set is 2n - 1 = 25 - 1 = 31.