Question

Set $A$ has $m$ elements and Set $B$ has $n$ elements. If the total number of subsets of $A$ is $112$ more than the total number of subsets of $B$, then the value of $m \cdot n$ is

Answer 1

$2^{m}-2^{n}=112$
$m=7, n=4$
$\left(2^{7}-2^{4}=112\right)$
$m \times n=7 \times 4=28$