The Actual Answer
Summary: Kakashi uses very specific wording and accidentally gets his point across.
It became pretty evident that their teacher had no intention of passing them.
He had said as much. Even so, he had decided to give them one last chance for a make up exam, after telling them their teamwork was shit.
After tying the weakest member of their team, dead last in the academy's class, to a pole, he had explained how things would be from then. "He'll remain tied to that pole. You're not allowed to feed him. You've got like, fifteen to twenty minutes to eat and get ready. I'll be back."
And then he left in a poof.
Sasuke had taken a few moments to make sure he wasn't watching, though it didn't occur to him that Kakashi could hide well enough to fool him because Sasuke was entirely too overconfident, then offered Naruto part of his food.
When Sakura protested, he explained that "if Naruto is weak then he'll drag us all down."
That was logical. Then Sakura remembered and had an idea. "Wait, wait," she said. "Kakashi said we couldn't feed him!"
"Yes, but he's not here," Sasuke argued.
"I can't believe this," Naruto said.
"I'm going to feed him. You keep watch in case he-" Sasuke began.
"Kakashi said we couldn't feed him, not that we can't free him!" Sakura interrupted.
Sasuke blinked. "Huh. Really?"
"Really?" Naruto repeated.
"Yes! He said, and I quote, 'You're not allowed to feed him', end quote."
Sasuke shrugged. Pulled off a kunai and freed Naruto. The three promptly sat down and divided their meals equally. Sasuke insisted that Sakura should not died as he found the very idea completely idiotic, and she couldn't exactly say no to him.
"Huh. Well, congratulations on looking underneath the underneath and beating me at my own game, kids," the teacher said, causing all three of them to jump into the air in fright.
"And that was basically it," Kakashi finished his report.
"Huh," the Hokage said. "So you let them pass because you screwed up the bell test?"
"Eh, they were willing to risk pissing me off to keep their team in top fighting shape. I say it's a pass."
Sarutobi shrugged and stamped his approval.