NFHS Basketball rule please
How many players must be on the floor to continue a game.

Situation ... team A with 7 players has 6 of them foul out. The game continued with player A inbounding the ball. Team B would take ball and eventually score. Player A repeated the sequence til time ended.

Here's the kicker ... team A won.
Game went almost 3 hours.
The level was 12 - 14 year old girls.

If the team still has a player to throw in the ball and they have a ligitimate chance to win then the game can continue.

I don't have my book with me at work so I don't have a rule reference but this came up a few years ago in our assoc.

5 to start, at least 1 after that unless the referee deems it to be not reachable. In your case if Team B was up by 50 points or whatever then the game would be called. But in this case that didn't happen because Team A was winning. That would of been something to see!