SOLUTION: #1: The speed of a stream is 6mph If a boat travels 54 miles downstream in the same time that it takes to travel 27 miles upstream, what is the speed of the boat in still water?

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Question 839076: #1:
The speed of a stream is 6mph
If a boat travels 54 miles downstream in the same time that it takes to travel 27 miles upstream, what is the speed of the boat in still water?
#2:
A cruise boat travels 12 miles downstream in 4 hours and returns to its starting point upstream in 6 hours.
Find the speed of the stream
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

The speed of a stream is 6mph

If a boat travels 54 miles downstream in the same time that it takes to travel 27 miles upstream, 

what is the speed highlight_green%28x%29 of the boat in still water?

D = rt  0r   t = D/r

Question states***

 +54%2F%28x+%2B+6mph%29+=+27%2F%28x+-+6mph%29  |Cross Multiply to solve for x



A cruise boat travels 12 miles downstream in 4 hours and returns to its starting point upstream in 6 hours. 

 Find the speed of the stream

  (r+c)4hrs = 12mi

  ((r-c)6hrs = 12mi

 4r + 4c = 12

 6r - 6c = 12

Solving for r by Elimination of c:

 24r + 24c = 72

 24r - 24c = 48

    48r = 120

      r = 2.5mph, speed of boat in still water   (current =  .5mph)