Answer
$ 51.39$ kilograms
Work Step by Step
Given \begin{equation}
W(a)=22.37 \sqrt[5]{a^3}.\tag{1}
\end{equation}
A) Find $W(4)$ for $a= 4$ years substituting $4$ for $a$ in equation $(1)$.
\begin{equation}
\begin{aligned}
P(3)&= 22.37 \cdot(4)^{\frac{3}{5}}\\
&\approx51.39.
\end{aligned}
\end{equation} A four year old alpaca weighs about $ 51.39$ kilograms.
