problem 1

Let $N$ be the number of ameobas in the pond after a minutes.

E (N) = \frac{1}{3} (0 + 2 + 1) = 1

Var (N) = E (N^{2}) - {(E (N))}^{2} = \frac{1}{3} (0 + 4 + 1) - 1 = \frac{2}{3}