Why did Hermione lie about the troll?

Question

I have tried to look at many answers to this question, since it is a rather common one, but with no satisfactory answer up until now.

The truth of the story is: Hermione was crying in the girls bathroom because of Ron's comments and didn't know about the loose troll, which is why Ron and Harry came to warn her.

The story Hermione tells: She read about trolls and thought she could take it on by herself. Harry and Ron probably saved her life.

What seems to be the ideal story: Simply leave out the part about crying because of Ron's comments, there are other obvious reasons why one might be in a bathroom.

Possible answers that could make sense:

1. The bathroom she was in wasn't the closest one to the great hall, so she would have had to explain why she was in that particular bathroom. Apparently she has been there "all afternoon", so perhaps that's why she needed to make sure not to reveal that she has been crying because of Ron and instead say she went looking for the troll. But this would raise the question of why she assumes the teachers would know for how long she was already in the bathroom.
2. Hermione assumed that Ron and Harry wanted to fight the troll. She didn't know they came to save her so she decided to take the blame instead.

Do any of these answers make sense? If not, I don't see any reason why she would lie.

A common answer to this question is "She wanted to shift the blame onto herself" but she wouldn't really accomplish that since Harry and Ron still disobeyed teachers orders in order to save Hermione regardless of her motives.

Answer 1

When the troll entered the bathroom, Hermione was too afraid to do anything more than scream. She was so afraid that she moved only after she was forced to. From what is told, trolls are stupid creatures and are not afraid to kill and/or maim people. From her point of view, Harry and Ron were VERY brave trying to take on a troll. Added to the fact that Hermione was at that time their second-worst enemy, she was touched that they were trying to save her life.

One might argue that it was Harry and Ron's fault for trapping the troll in the bathroom, but Hermione didn't know that. All she knew was that they saved her from a troll.

When the teachers heard the commotion that the troll made, they rushed to the bathroom, only to find that two first years had defeated the troll. Now, they would have been rewarded, but from the teachers' point of view, it was a dangerous task and they could have been killed.

Naturally, the teachers would ask why they tried to do that. In this context, Hermione knew that the teachers would scold the duo if they said that they wanted to take on the troll. As payback, Hermione took the blame on herself and told the teachers that she knew all about the troll and had decided to take it on herself, and that the duo had rescued her from what would have been a certain death. This lead to the teachers rewarding the duo with five points each and taking five points away because of 'Miss Granger'.

Now, to answer your original question of 'Why did Hermione lie?'. Hermione simply returned a favour. The duo saved her from death, she saved them from scolding (and possible detention).