Who was the youngest president of the United States?
system
Who was the youngest president of the United States?
user
The youngest person to become U.S. president was Theodore Roosevelt, who was 42 when he succeeded to the office after William McKinley's assassination in 1901. John F. Kennedy was the youngest to be elected since he was 43 when he became the 35th president in 1961. 
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Who was the youngest president of the United States?</s>
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The youngest person to become U.S. president was Theodore Roosevelt, who was 42 when he succeeded to the office after William McKinley's assassination in 1901. John F. Kennedy was the youngest to be elected since he was 43 when he became the 35th president in 1961. </s>
