SOLUTION: A boat can move at 8 miles/hour in still water. If it can travel 20 miles downstream in the same time, it can travel 12 miles upstream. Determine the rate of the stream.

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A boat can move at 8 miles/hour in still water. If it can travel 20 miles downstream in the same time, it can travel 12 miles upstream. Determine the rate of the stream.      Log On


   

Question 667752: A boat can move at 8 miles/hour in still water. If it can travel 20 miles downstream in the same time, it can travel 12 miles upstream. Determine the rate of the stream.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Boat speed = 8 mi/h
current speed = x mi/h
x
speed against wind 8 - x
speed with wind 8 +x

Distance against wind 12 miles
Distance with wind 20 miles

t=d/r time against = time with wind -
12/(8-x )=20/(8+x)
12(8+x)=20(8-x)
96+12x =160-20 x
20x+12x= 160 -96
32 x = 64
/ 32
x = 2 mi/h