15 correct.
The ones I got wrong were:
4. Who was President during the Great Depression and World War II? (Herbert Hoover)
7. Who is in charge of the executive branch? (the Chief Justice)
15. Name one state that borders Canada. (Rhode Island)
17. If both the President and the Vice President can no longer serve, who becomes President? (the Secretary of State)
20. When is the last day you can send in federal income tax forms? (July 4)