Harry Potter and the Goblet of Fire discussion

We all know how Harry found out about the second task: Dobby and Moaning Myrtle helped him, but also Cedric gave him the password to the Prefect's bathroom.
So, how did Krum and Fleur find out about what the task was and how to complete it?
If the egg had to be opened underwater in the Prefect's bathroom, then how did they get in?
I know Karkaroff and Madam Maxime would be willing to cheat, but that still doesn't explain how they found out how to even open the egg.
I'd appreciate your feedback :)

Who said the egg had to be opened in the Prefect's bathroom? That's just where Cedric happened to open it, and he suggested it to Harry as well, as it both provided a place to open the egg underwater, and had a picture of a mermaid on the walls, giving him the idea of merpeople in the lake.

Krum and Fleur had the help of their respective Headmasters, and probably the rest of their schoolmates as well. The adults would know the history of the Triwizard Tournament inside out, and knew what kind of tasks to expect. They also undoubtedly knew a lot more magic than Harry or even Hermione. They had plenty of advantages that Harry didn't.

Didn't Krum go swimming in the lake?

@Ciara, it didn't have to be in the prefect's bathroom. Anywhere underwater would do.

@Moonlight, yes, Krum opened it in the lake.

Thank you. I did know that it didn't neccesarily have to be opened in the Prefect's bathroom, but I thought that maybe there would only be certain places inside Hogwarts where it could be opened.
Thanks for clearing that up :)