CREATE TABLE table_20158 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "U.S. viewers  ( million ) " TEXT)

Name who wrote number 47
SELECT "Written by" FROM table_20158 WHERE "No. in series" = '47'
SELECT "Written by" FROM "table_20158" WHERE "No. in series" = '47'