Assume a Steiner triple system exists with parameters $b, v, k, r, \lambda$ where $k=3$. Let $a$ be the remainder when $\lambda$ is divided by 6 . Use Theorem $10.3 .1$ to show the following:
(i) If $a=1$ or 5, then $v$ has remainder 1 or 3 when divided by $6 .$
(ii) If $a=2$ or 4, then $v$ has remainder 0 or 1 when divided by $3 .$
(iii) If $a=3$, then $v$ is odd.