Question 1098320
<br>For the odds (n favor of) a particular outcome, the ratio is
(number of good outcomes) : {number of bad outcomes)<br>
For probability, the ratio is
(number of good outcomes) / (total of all possible outcomes)<br>
Note that it is customary to use the : when writing odds and the / when writing probabilities.  You will sometimes see probabilities written with the : but that is confusing to many people.<br>
There are 12 months, of which 7 have 31 days each and the other 5 do not.  So while the odds of a month having 31 days is 7:5, the probability of a month having 31 days is 7/12.