Position of youngest portion of secondary phloem and youngest region of  of secondary xylem in a 20 years old dicot stem in secondary growth is

Position of youngest secondary phloem is just outside the vascular cambium. Position of oldest secondary phloem is just inside the primary phloem. Position of youngest layer of secondary xylem is just inside the vascular cambium. Position of oldest layer of secondary xylem is just outside the primary xylem.