4. At a given time, the depth of snow in Kingston is $12.1 \mathrm{~cm}$ and the depth of snow in Hamilton is $18.6 \mathrm{~cm}$. Over the next thirteen hours, it snows at a constant rate of $2.6 \mathrm{~cm}$ per hour in Kingston and at a constant rate of $x \mathrm{~cm}$ per hour in Hamilton. At the end of these thirteen hours, the depth of snow in Kingston is the same as the depth of snow in Hamilton. What is the value of $x$ ?
4. The initial depth of snow in Kingston is $12.1 \mathrm{~cm}$ and it snows at a rate of $2.6 \mathrm{~cm}$ per hour, so after 13 hours, the depth of snow in Kingston is $(12.1+2.6(13)) \mathrm{cm}$.
The initial depth of snow in Hamilton is $18.6 \mathrm{~cm}$ and it snows at a rate of $x \mathrm{~cm}$ per hour, so after 13 hours, the depth of snow in Hamilton is $(18.6+13 x) \mathrm{cm}$.
Since the final depths are equal, then
$$
\begin{aligned}
12.1+2.6(13) & =18.6+13 x \\
45.9 & =18.6+13 x \\
13 x & =27.3 \\
x & =2.1
\end{aligned}
$$

Therefore, $x=2.1$.
ANSWER: 2.1