The odds against a horse winning a race are 6 to 5. What is the probability
of the horse winning the race?

Conversion formulas for ODDS IN FAVOR and AGAINST 
to and from PROBABILITY

1. If odds in favor of event E are "a to b" then P(E) = 

2. If odds against event E are "a to b" then P(E) = 

3. If P(E) = , then ODDS in favor of event E = "a to b-a"

4. If P(E) = , then ODDS against event E = "(b-a) to a"

We need formula 2:

2. If odds against event a horse winning a race are "6 to 5"
then P(horse winning the race) =  = 

Edwin