IBPS PO RRB PO Prelims 5 Aug 2023 Shift 3 Paper

The average age of a group of 4 friends was 23 years but after two years the oldest member of the group died and one year later another person joined there group now the average age of the group remains the same. What is the difference between the age of the new person added to the group and the age of person at the time of his death?