How do you beat the third gym badge black?

1. Get a Tirtouga (the water/ground fossil pokemon).
2. Raise it to level 31, where it learns Smack Down.
3. Keep the move Ancient power (which it should know).
4. Get a Drilbur and raise it to level 19 (when it learns Dig). Keep raising it into the high 20's.
5. Get a Blitzle for your electric type and raise it to level 27 when it becomes a Zebstrika.
6. Start with Zebstrika. Zebstrika makes the use of Volt Switch null and void because of its ability. get a few hits in with the Emolgas.
7. If she switches to her Zebstrika, switch to your Drilbur. Use Dig to hit it hard.
8. Keep going until she goes down. If you make her use her healing potions on her two Emolgas, she won't heal her Zebstrika.

That is how you beat her. Hope it helped.