How many beans make five?

6.25

Caveat: the above answer is only a ballpark statistical assumption.

In many jurisdictions there are statutory requirements relating to the sale of goods.  Of relevance to this discussion are the laws regarding 'fitness for use'.  Regulations covering the sale of seeds commonly require a germination rate of at least 80% under some set of standard conditions.

80% of 6.25 seeds produces how many bean plants?  You do the maths.

Of course, there are many varieties of beans.  Then there are various climatic conditions, soil types, fertilizers etc.  Now factor in the chances of fungal rot, insect and bird predation etc.

Someone, somewhere is going to come up with a nice mathematical formula for all this.

But it won't be me.