It's important to remember that the results of every race are a reflection of two key values:
The amount in the race pools
The number of people wagering on your given competitor
While the finishing order will also effect the payout (if you're making a multi-runner bet instead of just a "win") these two aspects are the primary drivers. So the payout number you see when placing your bet is the "Potential payout" based on the money in the pool at the time you placed your wager, divided by the number of people wagering on your competitor - both these aspects can change right up to the time of the race (and still be impacted after the race has gone off) because the system is gathering all the bets on that competitor from multiple different sources and calculating them. So while the "payoff" you see when placing your wager gives you some indication, it's still just a rough indication of the payoff.
Once the race is over, all the money in the pool(s) is divided by all the winning bettors and divided up. And you get your payoff based on that.
The results screen shows you the payout on a $1 wager for each finishing order - so depending on what you wagered, you multiply your wager by that win amount, to get your payout.
So for instance, if you see $123.00 win for choosing the right "First 2" - multiply that by your bet amount....(YES, you really can win that much money - and more - on one bet!)
If you'd like more info on odds, payoffs and pools, please check out this article:
https://intercom.help/rushracing/how-to-play-rush/odds-payoffs-and-pools