What's the Year average that's got Trim of LS/LT and Power of HP (KW)?
CREATE TABLE "engines" (
  "year" real,
  "trim" text,
  "engine" text,
  "power" text,
  "torque" text,
  "epa_2008_city" text
);
SELECT AVG("year") FROM "engines" WHERE "trim"='ls/lt' AND "power"='hp (kw)';