Answer:
Zaroff is defeated because of his own overconfidence and arrogance.
Step-by-step explanation:
In "The Most Dangerous Game" by 'Richard Connell', General Zaroff's is tricked by Rainsford and Zaroff gets defeated because of his own arrogance.
General Zaroff lived on Ship-Trap island. He was tired of hunting animals, so he started hunting humans to satisfy his thrill. Rainsford was his new victim. Zaroff boosts to Rainsford that killing is his "mathematical certainty" and since animals cannot compete with him, he switched to hunting humans. In overconfidence, he allowed Rainsford to stay after the first day of the competition.
Rainsford tricked Zaroff by making him think that he died but he returned to Zaroff's castle, where Rainsford kills him.