Posted by sheba on .
rowing. Abby rows 10 km upstream and 10 km back in a total time of 3 hours. The speed of the river is 5km/h.Find Abby's speed in still water.

algebra 
Anonymous,
10/(v5)+10/(v+5)=3
10(v+5)+10(v5)=3(v+5)(v5)
20v=3v^275
3v^220v75=0