Problem: From its discovery in 1930 until 2006, what was considered to be the Solar System's ninth planet?
Answer: pluto

Problem: In the USA during World War I, any reference to things German was considered unpatriotic, in order to avoid this problem which common foodstuff was called a 'Salisbury Steak'?
Answer: hamburger

Problem: "What is the meaning of the word ""micturition""?"
Answer: urinating

Problem: Which planet orbits the Sun four times in the time it takes the Earth to go round once?
Answer:
mercury