In 1940, there were about 10 brown tree snakes per square mile on the island of Guam, and in 2012, there were about 10000 per square mile.

(a) Find an exponential formula for the number, $N$, of brown tree snakes per square mile on Guam $t$ years after $1940$.
$N =$ help (formulas)

(b) On average, what was the annual percent increase in the population during this period?
% (Round to nearest 0.01%) help (numbers)