SOLUTION: A bow goes 240 miles downstream in the same time making go 160 miles upstream the speed of the current is 5 mph what is the speed of the boat in still water ?

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Question 1150162: A bow goes 240 miles downstream in the same time making go 160 miles upstream the speed of the current is 5 mph what is the speed of the boat in still water ?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52867) About Me  (Show Source):
You can put this solution on YOUR website!
.
A highlight%28cross%28bow%29%29 boat goes 240 miles downstream in the same time making go 160 miles upstream the speed of the current is 5 mph
what is the speed of the boat in still water ?
~~~~~~~~~~~~~~~~~~~~~~ 


Time equation is


    240%2F%28x%2B5%29 = 160%2F%28x-5%29


Cross multiply and simplify


    240*(x-5) = 160*(x+5)

    240 - 1200 = 160x + 800

    240x - 160x = 800 + 1200

      80x = 2000

        x = 2000%2F80 = 25


ANSWER.  25 mph.


CHECK.   240%2F%2825%2B5%29 = 240%2F30 = 8.

         160%2F%2825-5%29 = 160%2F20 = 8.    ! Correct !

Solved.


Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


The ratio of the distances is 240:160 = 3:2, and the times are the same. So the ratio of the speeds is 3:2.

Let x be the speed of the boat in still water. If the speed of the current is 5mph, then the upstream speed is x-5 and the downstream speed is x+5. So

%28x%2B5%29%2F%28x-5%29+=+3%2F2
3x-15+=+2x%2B10
x+=+25

ANSWER: The speed of the boat in still water is 25mph.