Question 996259: A boat can travel 29 mph in still water. If it travels 342 miles with the current in the same length of time it travels 180 miles against the current, what is the speed of the current?
Answer by fractalier(6550)   (Show Source):
You can put this solution on YOUR website! Call the rate of the current r.
We also know that rate times time equals distance. Thus, rt=d and t = d/r.
With the current, the boat's speed is 29 + r.
Against, it is 29 - r.
Since the times are equal, their d/r are equal...so
342/(29+r) = 180/(29-r)
Now cross-multiply and get
342(29-r) = 180(29+r)
9918-342r=5220+180r and
522r = 4698 and
r = 9 mph
|
|
|
