The Seven Treasurer aren't dungeons but items given to the player after they defeat the bosses in seven secret Wonder Mail dungeons.
You get the places after you rescue the Pokemon frostlass froze on blizzard island and getting the secret rank, then on random days the Pokemon that give you the jobs will give you jobs that tell you to get the seven treasures, one at each place. (mt. avalanche (20 floors), giant volcano (20 floors), mystery jungle (30 floors), bottomless sea (50 floors),shimmer dessert ( 40 floors), world abyss ((50 floors),and sky stairway. (50 floors ) then search "what to do after the seven treasures on Pokemon mystery dungeon.
48 floors
A dungeon is a cave on pokemon mystery dungeon. It is a level with a series of floors/rooms and the object is to get to the end of the dungeon.
30 floors
there is thirty floors
24 floors
there are 20 floors.
40
The Nightmare has 17 floors.
50 floors
there are 15 floors to this dungeon and a sandstorm on floors 6,10 and 11
there are 20 floors there are 20 floors