Keep scrolling down for answers and more stats ...
2. California and Washington
California: Apple, Facebook, Google. Washington: Amazon, Microsoft.
3. Nevada and North Dakota
4. New Mexico and Wyoming
7. Mississippi and Tennessee
9. South Carolina and West Virginia
Charleston is actually the largest city in both states
10. Missouri and Utah
St. Louis: 1904. Salt Lake City: 2002.
11. Alaska and Arizona
Arizona became a state in 1912. Alaska became a state in 1959.
12. Louisiana and Michigan
13. Arkansas and Connecticut
15. California and Wisconsin
Thanks for the quiz :)
It required a process of elimination for a number of the questions and that ultimately led me to the correct answers.