Chapter 13 - Counting and Probability - 13.3 Probability - 13.3 Asses Your Understanding - Page 866: 53

$0.63$

We know that $P(\text{an event happens})=1-P(\text{an event doesn't happen}).$ Hence, here (with $37\%=0.37$) we have $P(\text{does not own a cat})=1-P(\text{owns a cat})\\ P(\text{does not own a cat})=1-0.37\\ P(\text{does not own a cat})=0.63$