you cannot beat a ghost in lavender tower because your pokemon are too scared to fight them, however if you unmask them you may battle and defeat them. to unmask then you need the silph scope, which you can get from team rocket hideout, after beating giovanni. and unmasked ghost may either be a ghastly, haunter, cubone or if it is the boss ghost, it is cubone's mother marowak.
Yes.
Have ALOT of Water and Ghost Pokemon
You can beat a ghost type with another ghost type (Like Haunter)
Dark type can beat ghost.
Beat pokemon ghost tower and talk to mr. fuji at the top.
The Gym Leader is easy to beat. She mainly use's ghost type Pokemon. Ghost Pokemon are weak against Physic Pokemon. Trust me if i can beat her you can.
ghost
Go to game corner in celadon city and press the button in the poster and a secret door will open! go there and beat Giovanni. then you will get silph scope and return back to Pokemon tower to beat ghost and save mr.fuji he will give you a pokeflute
Lavender Town
Ghost and Psychic
thunder pokemon
I'm afraid there are no types of pokemon that can beat the Ghost type :P