SOLUTION: Kathryn row a boat downstream for 40 miles. The return trip upstream took 16 hours longer, If the current flows at 4mph how fast does Kathryn row in still water?
I am stuck as I
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-> SOLUTION: Kathryn row a boat downstream for 40 miles. The return trip upstream took 16 hours longer, If the current flows at 4mph how fast does Kathryn row in still water?
I am stuck as I
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Question 588188: Kathryn row a boat downstream for 40 miles. The return trip upstream took 16 hours longer, If the current flows at 4mph how fast does Kathryn row in still water?
I am stuck as I cant find an example in my text book with an explanation on how to solve Answer by mananth(16949) (Show Source):
You can put this solution on YOUR website! Boat speed = xmph
current speed = 4mph
sped with current = x+4 mph
speed against current = x-4 mph
t= d/r
time taken with current =
40/(x+4)
time taken against current = 40/(x-4)
40/(x-4) =40/(x+4) + 16
40/(x-4) -40/(x+4) =16
LCD = (x+4) (x-4)
multiply by the LCD
40(x+4) -40(x-4) = 16(x^2-16)
40x+160-40x+160 = 16x^2-256
16x^2= 320 +256
16x^2=576
x^2= 576/16
x^2= 36
x= +/- 6
speed of boat = 6 mph
