Victoria was the daughter of Prince Edward, Duke of Kent and Strathearn, the fourth son of King George III. Both the Duke of Kent and King George III died in 1820, and Victoria was raised under close supervision by her German-born mother Princess Victoria of Saxe-Coburg-Saalfeld. She inherited the throne aged 18, after her father's three elder brothers had all died, leaving no surviving legitimate children. The United Kingdom was already an established constitutional monarchy, in which the sovereign held relatively little direct political power. Privately, Victoria attempted to influence government policy and ministerial appointments; publicly, she became a national icon who was identified with strict standards of personal morality.
Try to answer this question if possible (otherwise reply "unanswerable"): At what age did Victoria inherit the throne, upon the death of her father's three eldest brothers?
18