Question

How many elements must a set have if the number of proper subsets of the set is one half

of the total number of subsets of the​ set?

Answer 1

2^n - 1 = 1/2(2^n)
2^1 - 1 = 2^1/2
2 - 1 = 2/2
1 = 1

Theefore, the set must have one element