G10.1 Each interior angle of an $n$-sided regular polygon is $160^{\circ}$. Find $n$.
G10.2 The $n^{\text {th }}$ day of May in a year is Friday. The $k^{\text {th }}$ day of May in the same year is Tuesday, where $20<k<26$. Find $k$.
Each exterior angle $=20^{\circ}$ (adj. $\angle \mathrm{s}$ on st. line)
$$
\begin{array}{l}
\frac{360^{\circ}}{n}=20^{\circ} \\
\Rightarrow n=18 \\
18^{\text {th }} \text { May is Friday } \\
22^{\text {nd }} \text { May is Tuesday } \\
\Rightarrow k=22
\end{array}
$$