Hint for 7: See Fibonacci example on pp. 49-50.
Challenge problem: 22a - See how tight a bound you can get! Prize for best exact solution (with correct proof of upper bound) whose big-"O" bound is at least as good as mine. Prize is I will take you to lunch at your favorite Williamstown restaurant. (Strict honor code guidelines apply - no assistance from any person or text!)
The winners were Jason Schweinsberg and Joe Vanderwaart. Congratulations!