How much Grid has a Time/Retired of +0.785, and Laps larger than 29?
CREATE TABLE "125cc_classification" (
  "rider" text,
  "manufacturer" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);
SELECT SUM("grid") FROM "125cc_classification" WHERE "time_retired"='+0.785' AND "laps">29;