Slot Machine results are random, so it's possible for the jackpot combination to show up two spins in a row, or not at all for 20,000, 50,000, 100,000 or even more spins. But as a long-term average, the slots jackpots in our hypothetical casino show up an average of once per 10,000 spins.
In most slots, the rate is somewhere between 80% and 95%, but some games can exceed 95%. The basics of the return to player percentage indicate that if you betR$100 on a game with an RTP of 94%, you'll win backR$94. But again, this is for long-term results since the rate was determined over millions of spins.