Odds of 3-5 indicate that your profit will be three-fifths of a dollar. In other words, for everyR$5 you bet you can winR$3 in profit. To determine profit, multiply the amount you bet by the fraction. If I spendR$15, then my profit for winning isR$9 (15 x 3/5).

How to convert odds to probability and odds to a probability

1
To convert from a probability to odds, divide the probability by one minus that probability. So if the probability is 10% or 0.10 , then the odds are 0.1/0.9 or '1 to 9' or 0.111.
2
To convert from odds to a probability, divide the odds by one plus the odds.