Answer:
765,625 names if each says their own name, 764,750 if they don't. (Although, if you wanna get technical, only 875 names are being said, since they're repeating the same names over and over again)
Explanation:
Alrighty, this is complicated. Just to make it easier, we're going to switch the word "names" to "words."
There are 875 people in the room, and each one of them is saying 875 words (assuming it includes their own name). So to figure out how many words would be said, you multiply 875 by 875, which gives you 765,625 words. If they say everyone's name EXCEPT their name, then subtract 875, which gives you 764,750.