Question

The number of non-empty subsets of the set $\{1,2,3,4\}$ is ___.

• A. 15
• B. 14
• C. 16
• D. 17

Answer 1

The correct option is A 15

If a set has $n$ elements, then it has $2^n$ subsets.
But, empty set is a subset of every set.
$\Rightarrow$ The number of non-empty subsets of a set of $n$ elements is $2^n-1.$
Given the set $\{1,2,3,4\}$ with 4 elements.
Thus, the number of non-empty subsets of the set is $2^4-1=15.$