Answer
$164$ owned cats or dogs.
Work Step by Step
If $A$ is the set of people who owned cats, and $B$ is the set of people who owned dogs, then:
$n(A)=96$ people owned cats.
$n(B)=97$ people owned dogs.
$n(A\cap B)=29$ people owned cats and dogs.
$n(A\cup B)=?$ people who owned cats or dogs.
The formula for the cardinality of the union of two sets:
$n(A\cup B)=n(A)+n(B)-n(A\cap B)$
$n(A\cup B)=96+97-29=164$
$164$ owned cats or dogs.
