R.I. Gen. Laws § 44-19-16

Unless a hearing has been requested as provided in § 44-19-17, any determination made by the tax administrator under §§ 44-19-11 — 44-19-14 becomes final and shall be paid within ten (10) days after mailing by the tax administrator of the notice of that determination. If that determination is not paid, a further penalty of ten percent (10%) of the amount of the determination, exclusive of interest and other penalties, is added to it.