2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/72991We show that there exist noncommutative Ore extensions in which every right ideal is two-sided. This answers a problem posed by Marks in Duo Rings and Ore extensions, J.Algebra 280(2), (2004). We also provide an easy construction of one sided duo rings.Rings and Algebras16S32, 16D25text