IKMC 2024 - Grades 5-6 - Set 2 - Self-study Question 12

Five chocolate boxes A, B, C, D and E originally contain flavours numbered 1–5, 2–6, 3–7, 4–8 and 5–9 respectively. After most chocolates are eaten, one remains in each box, as shown. What is the label of box X, containing flavour 5?