A game with an estimated duration of 1499s is considered which time control?

N/A

The issue with trying to answer this is the fact that time controls can have multiple bonus times and can change partway through a game. It's similar to integrating where there's always a constant of integration that you can't solve for without further information than just the derivative. Anyway, I'll give you a few that could average to that number if they played 100 games:

- 20+0
- 18 d5
- 15 +5
- 10 +10
- 40/15 SD/10 +0

This kind of speed is a slow rapid game; it's just a bit too fast to be considered classical.

obviously rapid. though you can't achieve that mathematically with the settings you're offered.

The closest you can get is 1.5+35 = 1490

Thing is lichess defines time controls like this

< 29s = UltraBullet
< 179s = Bullet
< 479s = Blitz
< 1499s = Rapid
≥ 1500s = Classical

where time = start + 40 * increment

It looks like there are a few places in the source code that evaluate the time control category. This seems like a good representative:

setupCtrl.ts says:
> const totalGameTime = time * 60 + increment * 40;
> return totalGameTime < 30
> ? 'ultraBullet'
> : totalGameTime < 180
> ? 'bullet'
> : totalGameTime < 480
> ? 'blitz'
> : totalGameTime < 1500
> ? 'rapid'
> : 'classical';

So 1499 would also be rapid.

But I would call these "half game" durations, since the time control numbers apply to each side. A "ten minute game" lasts about 20 minutes.