CREATE TABLE table_24135 ("Rank" FLOAT, "Average" TEXT, "Player" TEXT, "Runs" FLOAT, "Innings" FLOAT, "Not Out" FLOAT, "Period" TEXT)

What period was there a career average of 48.15?
SELECT "Period" FROM table_24135 WHERE "Average" = '48.15'
SELECT "Period" FROM "table_24135" WHERE "Average" = '48.15'