SOLUTION: a boat goes 14 km/h in still water. The boat is paddled 6 km downstream in a river in the same time it takes to go 3 km upstream. What is the speed of the river?

Question 356149: a boat goes 14 km/h in still water. The boat is paddled 6 km downstream in a river in the same time it takes to go 3 km upstream. What is the speed of the river?
Found 2 solutions by mananth, robertb:
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
a boat goes 14 km/h in still water. The boat is paddled 6 km downstream in a river in the same time it takes to go 3 km upstream. What is the speed of the river?
...
speed in still water = 14 km/h
speed of current be x
..
speed downstream = x+14
spped upstream = 14-x
...
Time = distance /speed
time upstream = 3/(14-x)
speed downstream = 6/x+14
..
the times are same
3/(14-x) =6/(x+14)
3(x+14)=6(14-x)
3x+42=84-6x
9x=84-42
3x+6x=42
9x =42
x=4.66 km/h
...
m.ananth@hotmail.ca
Answer by robertb(5830) (Show Source): You can put this solution on YOUR website!
let x = speed of the river. Then 14 + x = speed of boat relative to the river DOWNSTREAM, and 14 - x = speed of the boat relative to the river upstream.
Using the formula D = RT, and knowing the fact that the times upstream and downstream are the same, then
,
,
,
,
km/hr, the speed of the river.
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