Odds

Odds are 10 to 1 it will rain tomorrow.

10 10

P(rain) = ---------- = -------

10 + 1 11

Suppose P(A) = 1/4

Then O(A) = (1/4) / (3/4) = 1/3

P(A) P(A)

in general: O(A) = -------- = -----------

P(~A) 1 - P(A)