SOLUTION: "A boat's crew rowed 39 kilometers downstream, with the current, in 3 hours. The return trip upstream, against the current, covered the same distance, and it took 13 hours. Find th

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Question 1102342: "A boat's crew rowed 39 kilometers downstream, with the current, in 3 hours. The return trip upstream, against the current, covered the same distance, and it took 13 hours. Find the crew's rowing rate in still water."
The question does not say how fast (mph) the current is like the examples we covered in the class powerpoints.
Am I missing something in order to set this up properly?
13(x-?)=3(x-?)
Found 2 solutions by josgarithmetic, richwmiller:
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
                  SPEED           TIME         DISTANCE
DOWNSTRM          r+c             3             39
UPSTREAM          r-c            13             39

BASIC RULE: RT=D


system%28%28r%2Bc%29%2A3=39%2C%28r-c%29%2A13=39%29

system%28r%2Bc=13%2Cr-c=3%29

Simple use of elimination:
r%2Bc%2Br-c=13%2B3
2r=16
highlight%28r=8%29

choosing either of the most simplified equations,
highlight%28c=5%29

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
"A boat's crew rowed 39 kilometers downstream, with the current, in 3 hours. The return trip upstream, against the current, covered the same distance, and it took 13 hours. Find the crew's rowing rate in still water."
The question does not say how fast (kph not mph) the current is like the examples we covered in the class powerpoints.
Am I missing something in order to set this up properly?
13(x-?)=3(x-?)

Try:
3(s+c)=39
13(s-c)=39
Two equations with two unknowns
rate in still water (s) and current (c)