SOLUTION: A boat traveled 210 miles downstream and back. The trip dwonstream took 10hours. The trip back took 70 hours. What is the speed of the boat in still water? What is the speed of the

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A boat traveled 210 miles downstream and back. The trip dwonstream took 10hours. The trip back took 70 hours. What is the speed of the boat in still water? What is the speed of the      Log On


   

Question 1013929: A boat traveled 210 miles downstream and back. The trip dwonstream took 10hours. The trip back took 70 hours. What is the speed of the boat in still water? What is the speed of the current?
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Call the rate in still water, r.
Call the rate of the current, c.
Then we have
r + c = 210/10 = 21
r - c = 210/70 = 3
Add these and get
2r = 24
r = 12 mph
c = 9 mph