how many time is fri 27 aug 19' 38.87 115.219mph?
CREATE TABLE "2010_junior_manx_grand_prix_practice_tim" (
  "rank" real,
  "rider" text,
  "sat_21_aug" text,
  "mon_23_aug" text,
  "tues_24_aug" text,
  "wed_25_aug" text,
  "thurs_26_aug" text,
  "fri_27_aug" text,
  "sat_29_aug" text
);
SELECT COUNT("sat_29_aug") FROM "2010_junior_manx_grand_prix_practice_tim" WHERE "fri_27_aug"='19'' 38.87 115.219mph';