My own reasoning behind why Sooyoung told Sunny that the answer is either 3 or 4 (Girls Go To School episode 1)

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On the night of their first filming for Girls Go to School, they all go to sleep way later than they expect they should have. Seohyun keeps fretting that they're going to be too tired tomorrow, but her eight unnies just giggle and ruffle her hair. They're huddled up on the floor in what should be their lounge, the balloons still hanging from the wall. Every now and then, Sunny flicks one and it bounces on Sooyoung's head.

"We're debuting," Yuri mutters, wonderous, because this is all becoming a reality now. Perhaps they've faced some criticism, but it's happening - their dreams are coming true.

"Do you like living together?" Tiffany raises her head from where it lay on Taeyeon's lap. She had been so excited when their manager had announced their moving in together, but the others didn't seem so enthusiastic.

"It's more fun than I expected," Jessica comments. "Now I can live with eight members who mean so much to me."

"Until we wake you up in the morning..." Hyoyeon adds, sounding distinctively more lively than most of the other girls.

Some of them have only known each other for a handful of time. Even as trainees, they didn't have a great deal of time together. As members were being added or removed, they were just fighting to stay in the run up. Yet as soon as they were given their debut song and told to adjust to their official members, everybody came together. They spent days and nights together practicing, recording and getting each tiny detail perfect. If they were going to be a group together, then they had to learn to appreciate each other.

"It's nice to know that there'll always be people to come home to at the end of a busy schedule," Taeyeon says, because she knows that she has a tendency to feel lonely and she feels like these eight girls already know her better than anyone. "That I'll never be lonely."

"Yeah," Yoona nods. "Whenever we're tired or sad, there'll be another eight girls here to make us smile."

They fade back into silence then, still clutching onto one another. Seohyun's eyes are droopy and Jessica keeps moving with a jolt as though she's drifting in and out of sleep. That's when they make a mutual agreement to move to Yoona, Taeyeon and Sooyoung's room where the beds are all pushed together as though it's one large bed. Yoona, Taeyeon and Sooyoung immediately lie down on their respective beds, and the others slot in between them. Yuri huddles up beside Yoona, Seohyun and Tiffany, who's next to Taeyeon, where Sunny, Hyoyeon and Jessica lie with Sooyoung at the end.

"Can't we all just sleep like this?" Jessica groans, burying her head inside Hyoyeon's curls.

"You'd push me off the bed," Sooyoung complains. "If you had a nightmare, you'd deafen us all and kick us all. It'd be a disaster."

"It is comfy, though," Tiffany admits, cuddling up beside Taeyeon.

"I've got a test tomorrow," Sunny sighs, moving into Taeyeon's touch as she wraps her arms around her waist beneath the covers. "How can I concentrate on the test when we've got a performance straight after?"

"Guess your way through it," Taeyeon jokes. "We're idols now, we don't need test results!"

"Three."

"What?"

"Four..." a snore erupts from Sooyoung's end of the conjoined beds, slightly muffled.

"Jessica, what are you talking about?" Sooyoung raises her head and begins to poke Jessica's. "Are you sleeping? Sica!"

All eight of the remaining conscious girls began to roll with laughter.

"Hey, Sunny," Sooyoung calls across the beds. "I think Jessica's trying to tell you the answers. It's either three or four!"

"Thanks Sica, I'll remember that," Sunny holds a thumbs up.

"Maybe Sica and I should go back to our beds," Hyoyeon cradles Jessica's head, sniggering at the girl who so easily falls asleep.

"What if we stay here, just for tonight?" Seohyun's proclamation shocks everybody. "It's so warm and comfortable here. I feel safe and content."

Yoona grins, finding Seohyun's comment absolutely adorable. She their maknae's head and snuggles closer. "I agree with Seohyun. Just for tonight, can we stay together?"

When nobody responds, all they hear is a great snore escapes from Jessica again. That settles it, then, they're staying together for tonight.