Fredal
34

# a paddle boat can move at a speed of 6km/h in still water. the boat is paddeled 16km downstream in a river in the same time it takes to go 8km upstream what is the speed of the river?

$v-the\ speed\ of\ the\ river\\\\16:(6+v)=8:(6-v)\\\\\frac{16}{6+v}=\frac{8}{6-v}\\-------------\\multiply\ on\ the\ cross\\-------------\\8(6+v)=16(6-v)\\\\48+8v=96-16v\\\\8v+16v=96-48\\\\24v=48\ \ \ /:24\\\\v=2\ (km/h)\leftarrow Answer$