1) Who shot President William McKinley in 1901?
Answer: Leon Czolgosz
James Earl Ray
John Hinckley, Jr.
Charles J, Guiteau

2) How many states joined the Union in the 20th century?
Answer: 5

3) What national landmark opened in Washington D.C. in 1922?
The Pentagon
The Washington Monument
Answer: The Lincoln Memorial
The Jefferson Memorial

4) Which census declared that the U.S. population had reached 100 million?
1910, 1920, 1930 or 1940?
Answer: 1920