how do i defeat the the battle tower Tycoon?

Do you mean the fight at the end of the 3rd streak? If yes, you can just start your team with a Starmie with these moves:

-Surf
-Ice Beam
-Thunderbolt
And preferrably, a nature that doesn't reduce Sp.Atk or Speed.

Ice Beam should KO Dragonite in one turn, and Surf should do the same to Rhyperior, while Thunderbolt doesn't KO Milotic easily should be enough.

You can have it hold a Lum Berry (cures any status effect), which will help if Milotic ends up confusing Starmie, or if somehow Dragonite gets a Thunderwave on Starmie.

Make sure the rest of your team aren't all bad against the pokemon he uses. They're always the same. Just in case Starmie loses.

If for whatever reason you don't want to get a Starmie like this, you could start the battle with a female Gyarados instead. Easy to find.

-Waterfall
-Ice Fang
-Dragon Dance
-Maybe Thrash for the last move

Have it hold a Lum Berry, this one needs it.
As the battle starts, use Dragon Dance once. This will make Ice Fang strong enough to KO Dragonite in one turn, and Waterfall with Rhyperior.

If Palmer starts with Dragonite, it might use Thunderwave while Gyarados uses Dragon Dance, but the Lum Berry will instantly heal it, no problem.
With Milotic, you can either keep using Waterfall, which won't do much damage every time, or go with Thrash which is stronger but leaves you confused after, but the Lum Berry, if not used already, heals this.