Drawing only Major Arcana in a Spread.

scrivener

In a celtic spread(or in any spread), How rare is it for a person to draw ONLY Major Arcana cards when using all the 78 cards? For example, In celtic spread a person draws 10 major arcana cards and no minor arcana cards at all. I know that mathematically it's next to impossible, but then again when dealing with tarot math goes out the window.
 

Lareia

It's been a while since I did this kind of thing the last time, but I believe it's calculated like this.

Assuming complete randomness in the distribution of majors throughout the entire deck, you have an initial 22/78 chance to draw a major. With each one, that chance changes- 21/77, 20/76 etc. If ypu.multiply those, you should get the probality, that is, you do 22/78 * 21/77 * 20/76 and so in until you have as many cards as are in your spead.
I'm running out if time before I have to leave, so feel free to calculate that yourself if you want- it should be astronomically low, hahah.