Four

Hermione looked up, shocked to see what appeared to be three other versions of her right in front of her. All the symptoms seemed to indicate she was under the effects of that duplication spell, but to see it with her own eyes was its own shocking matter. Since there were four of them both her and her duplicate must've been hit with the spell immediately after the split, or otherwise there was an error in the book. Good thing it ripped apart clothes as well, because it allowed Hermione to confirm that not a single spot was different between the four of them. It wasn't an excuse for her to examine her own hot and sexy body, not at all.

"So if you're the exact same as me..." The four Hermiones spoke at the same time, seemingly confirming that the four were exactly the same. "Then who used the spell on us?"

"Who's there!?" The Hermiones froze. They were in the library and out in the dorms much later than they should, so if they were spotted here with a forbidden spell cast on them no less they could potentially be expelled. Luckily before coming here Hermione asked Harry for his Invisibility Cloak, and they tried to quickly cover themselves with it before they were spotted.

Things didn't go as hoped though. The cloak wasn't made to hide four people under, and so there was some silent brawling as all four of them attempted to fit snuggly under the cloak. Legs, arms, and heads would be repeatedly pushed out, and their was quite a bit of pushing and shoving, until the voice they heard earlier came up to them and lifted the cloak off their heads.

The Hermiones looked up in anticipation, hoping a staff member didn't spot them.