recall your d = rt, distance = rate * time.
bear in mind that, say if the still air speed of the plane is say "p", and the wind has a speed of say "w", when the plane is going with the wind is not really going at "p" mph, is going at "p + w" mph.
likewise, when the plane is going against the wind, is not going "p" mph either, is really going "p - w", because the wind is eroding speed from it.
[tex]\bf \begin{array}{lccclll}
&\stackrel{miles}{distance}&\stackrel{mph}{rate}&\stackrel{hours}{time}\\
&------&------&------\\
\textit{against the wind}&1743&p-w&3\\
\textit{with wind}&2103&p+2&3
\end{array}
\\\\\\
\begin{cases}
1743=3(p-w)\\
\frac{1743}{3}=p-w\\
581=p-w\\
\boxed{w}=p-581\\
--------\\
2103=3(p+w)\\
\frac{2103}{3}=p+w\\
701=p+w
\end{cases}
\\\\\\
701=p+\left( \boxed{p-581} \right)\implies 701+581=p+p
\\\\\\
1282=2p\implies \cfrac{1282}{2}=p\implies 641=p[/tex]
so, what's the speed of the wind anyway? well, w = p - 581.
