What is the average feet that has a Latitude (N) of 35°48′35″, and under 8,047m?
CREATE TABLE "history_of_conquest" (
  "peak" text,
  "metres" real,
  "feet" real,
  "latitude_n" text,
  "longitude_e" text,
  "prominence_m" real
);
SELECT AVG("feet") FROM "history_of_conquest" WHERE "latitude_n"='35°48′35″' AND "metres"<'8,047';