Getting a 'three-way' option in a mission?

[Stewy1]

Ok, no giggling about the thread title...

I wanted to set up a mission where there is an equal one chance in three for an option or mission orders to occur.

I know, for an equal 1 in 4 chance, I:

* place 2 sailboats at 50% probability somewhere on the map
* then set up the mission triggers so that:
* Sailboat 1 exists (and no Sailboat 2 exists) = 1st mission
* Sailboat 2 exists (and no Sailboat 1 exists) = 2nd mission
* Both Sailboats exist = 3rd mission
* No Sailboats exist = 4th Mission


...but for equal 1 in 3 chance of a mission, is it:
* place three Sailboats at 50% somewhere on the map
* If Sailboat 1 exists (and no Sailboat 3) = Mission 1
* If Sailboat 2 exists (and no Sailboat 3) = Mission 2
* If Sailboat 1 OR 2 exists AND Sailboat 3 exists = Mission 3

Mathematically, does that work out to an equal one chance in three of the mission occurring?

Thanks guys - Math isn't my strong suit - so I wanted to ask
Stew