How many lbs of raw potatoes for mashed potatoes?

I had to look this up. In the past, we would just cook a 10 # bag and hope it would work for our group of about 25.

Here it is - 3 computer mouse sized potatoes will feed four people (1/2 c. serving each).

https://www.leaf.tv/articles/how-to-figure-out-how-many-potatoes-for-mashed-potatoes-for-the-number-of-people/