SOLUTION: Mister "W" took 20 minutes to drive his boat upstream to his favorite fishing place. His return trip home( downstream) at the same boat speed took him 10 minutes. the current in th

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Question 335571: Mister "W" took 20 minutes to drive his boat upstream to his favorite fishing place. His return trip home( downstream) at the same boat speed took him 10 minutes. the current in this part of the river is 3 mph. How far away is his favorite fishing place?
I tried this X.20min=30min.mph
X=3/2
d=30 mile
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
let the speed in still water be x mph
..
time taken = 20/60 = 1/3 hours
speed upstream = x-3
distance = speed * time
distance = (x-3)*1/3
..
down stream speed = x+3
time = 10/60 = 1/6 hours
..
distance = (x+3)*1/6
..
1/6*(x+3)=1/3*(x-3)
3*(x+3)=6*(x-3)
3x+9 = 6x-18
-6x+3x = -9-18
-3x=-27
x= 9
x= 9 mph
...
speed upstream = 9-3= 6 mph
time taken =1/3 hours
Distance = 1/3 * 6 = 2 miles.