Final answer:
Al Capone was around 40 years old when his criminal operations ended with his arrest and conviction for tax evasion.
Step-by-step explanation:
The notorious Chicago crime boss Al Capone was approximately 40 years old when his reign came to an end. Capone's criminal enterprise, which included bootlegging, gambling, and even murder, collapsed when he was convicted for tax evasion and sentenced to 11 years in prison in 1931. Notably, Capone's imprisonment included time at California's infamous Alcatraz prison. This marked the conclusion of his command over the Chicago Outfit or mafia, bringing his powerful and violent rule to a definitive close.