When calculating a probability, we are comparing the number of positive outcomes to the number of possible outcomes. Calculating the odds O against an event occurring, however, is the ratio of negative outcomes to positive outcomes.
O=Negative Outcomes/Positive Outcomes
Now we can look at the spinner and find the number of positive and negative outcomes.
On the spinner there are 1 green, 2 red, and 3 blue parts. We want to find odds against green, so the number of positive outcomes is equal to the number of green parts on the spinner. The number of negative outcomes is equal to the sum of all parts that are not green.
Positive:& 1green
Negative:& 2red +3 blue= 5not green
Let's form our ratio and then simplify it as much as possible.
