Let A= 1,2,3,4,5,6,7,8,9,10 . Then the number of subsets of A containing exactly two elements is

Step-by-step solution

A= 1,2,3,4,5,6,7,8,9,10 Number of subsets of A containing two elements aligned & =9+8+7+6+5+4+3+2+1 & 9(9+1) 2 = 90 2 =45 aligned Option (C) is correct Alternate Method The number of subsets of A containing exactly two elements is: ¹⁰ C ₂= 10 9 2 1 =45