Answer
$344.1$ meters per second
Work Step by Step
Given \begin{equation}
v(T)=20.1 \sqrt{273+T}.\tag{1}
\end{equation} Find $v(20)$ by substituting $T$ by $20$ in equation $(1)$: \begin{equation}
\begin{aligned}
v(20)&=20.1 \sqrt{273+20}\\
&=344.1
\end{aligned}
\end{equation} At a temperature of $20^{\circ} \mathrm{C}$, the speed of sound in air is about $344.1$ meters per second.
