Respuesta :
Let's use the constant motion equation: d = v*t, to express the equation for each case. But first, let's find the speed.
[tex]v=\frac{d}{t}=\frac{108mi}{3hr}=36\cdot\frac{mi}{hr}[/tex]The speed going upstream is 36 mi/hr.
[tex]v=\frac{108mi}{2hr}=54\cdot\frac{mi}{hr}[/tex]The speed going downstream is 54 mi/hr.
Observe that the distance traveled is the same.
Once we have the speed for each case, we can form the following system of equations.
[tex]\begin{gathered} x-y=36 \\ x+y=54 \end{gathered}[/tex]The first equation represents the difference between the motorboat speed in still water (x) and the rate of the current (y).
The second equation represents the addition between these two rates x and y. One equation represents the situation where the speeds are in opposite direction, and the other one represents when the
