SOLUTION: a boat traveled 176 miles each way downstream and back. The trip downstream took 11 hours. The trip upstream took 22 hours. What is the boat's speed in still water? what is the

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: a boat traveled 176 miles each way downstream and back. The trip downstream took 11 hours. The trip upstream took 22 hours. What is the boat's speed in still water? what is the      Log On


   

Question 1168185: a boat traveled 176 miles each way downstream and back. The trip downstream took 11 hours. The trip upstream took 22 hours. What is the boat's speed in still water? what is the speed of the current?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
r, boat without current
c, current's speed 

         SPEED       TIME      DISTANCE
DOWN      r+c         11         176
UPSTR     r-c         22         176

Using S=D%2FT
-
The downstream data gives you r%2Bc=176%2F11=16.
The upstream data gives you r-c=176%2F22=8

This system can easily be solved using Elimination Method:
system%28r%2Bc=16%2Cr-c=8%29

Add the corresponding members to eliminate c, and quickly find value for r.
Now, any method you like, easily find the value for .

system%28highlight%28r=12%29%2Cand%2Chighlight%28c=4%29%29