How long did the lock out last?

The movie makes it seem like only a week or two passed before Carter let them play again. Realistically it would take a lot longer than that for the players to get their GPA up to the required amount, especially if they were failing and ditching so many classes. The only way they'd be able to raise their grade so fast would be to redo all the work and tests they failed or got zeros on, and in high school most teachers don't let you redo work. Did they not all raise their GPA but Carter saw the progress they made and decided to let them play again? Or was the gym actually locked for way longer than the movie makes it seem?