Can you tell me the total number of Zone than has the Station users 2007-08 larger than 243,800, and the Year opened of 1855?
CREATE TABLE "stations" (
  "station" text,
  "year_opened" text,
  "metropolitan_borough_c" text,
  "zone" real,
  "station_users_2006_07" real,
  "station_users_2007_08" real
);
SELECT COUNT("zone") FROM "stations" WHERE "station_users_2007_08">'243,800' AND "year_opened"='1855';