Question

If $A=\{x:x=n^2,n=1,2,3\}$, then number of proper subsets is

• A. $3$
• B. $8$
• C. $7$
• D. $4$

Answer 1

Answer: (C)

Given that, $A=\{x:x=n^2,n=1,2,3\}=\{1,4,9\}$
$\therefore$ Number of elements in $A$ is $3$.
So, number of proper subsets $=2^3-1=7$