QUES: Q: What instrument did Chopin play for Charles Halle when the latter visited him?
A: Late in 1844, Charles Halle visited Chopin and found him "hardly able to move, bent like a half-opened penknife and evidently in great pain", although his spirits returned when he started to play the piano for his visitor.
Does the answer answer the question?

ANS: yes

QUES: Q: What is Thuringia's highest mountain?
A: Most of this range is forested and the Groer Beerberg (983 m) is Thuringia's highest mountain.
Does the answer answer the question?

ANS: yes

QUES: Q: What happened on BBC's Newsnight in 1998?
A: In exchange for Rupert Murdoch's support, Blair agreed not to join the European Exchange Rate Mechanism which John Major had withdrawn the country from in September 1992 after barely two years.
Does the answer answer the question?

ANS: no

QUES: Q: What is von Neumann algebra?
A: Von Neumann introduced the study of rings of operators, through the von Neumann algebras.
Does the answer answer the question?

ANS:
no