Vector Image available also as jpeg How many px?

When you send a vector image Adobe also makes it available in jpeg format. If you buy the vector format you don't need to know how many px the image is made up of.

But if a buyer chooses the jpeg format because he is not interested in the vector I'm wondering:

what logic does Adobe use to establish how many pixels to create the jpeg image to deliver to the buyer?

Will Adobe generate it from vector by enlarging it by how much? How many Px? How many DPI (72? 96? 300?... the customer may want to print it).

Is there a calculation that allows me to know for each image I send how the jpeg (or transparent png) will be distributed to those who purchase it in terms of px dimensions?

Thank you.