This means you'll win x dollars for every 1 dollar you bet. For example, a single-number bet offers a payout of 35:1. So, if you win, you'll get your dollar back plusR$35.
If you place aR$5 bet on a single number in roulette and that number hits, you will typically win $175. This is because the payout for a successful single-number bet (also known as a "straight bet") in American roulette is usually 35 to 1.