premise: Mary Isobel Downer, Lady Downer (13 December 1924 – 14 October 2014) was a prominent South Australian patron, wife of federal MP and high commissioner Sir Alexander "Alick" Downer, and mother of Liberal Party leader, Australian Foreign Minister and high commissioner Alexander Downer.
hypothesis: Lady Downer lived to be 100.
reason: If she was born in 1924 and died in 2014, she would have been 90.