If a set has 2 elements, how many non-empty proper subsets does it have?
Answer: B
Let A = {a, b}.
The total number of subsets is \(2^2 = 4\). The subsets are ∅, {a}, {b}, {a, b}.
A proper subset is a subset that is not equal to the original set. So, we exclude {a, b}. This leaves 3 proper subsets: ∅, {a}, {b}.
A non-empty proper subset excludes the empty set (∅). This leaves 2 non-empty proper subsets: {a} and {b}.