SOLUTION: If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are ________?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are ________?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 601587: If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are ________?
Found 2 solutions by lwsshak3, Alan3354:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are:
**
let x=rate of speed of boat in still water
let c=rate of speed of current
net speed of boat downstream=x+c
net speed of boat upstream=x-c
distance = travel time*speed
..
3(x+c)=72
6(x-c)=72
..
3x+3c=72
6x-6c=72
..
6x+6c=144 (mult.by 2)
6x-6c=72
add
12x=216
x=18
6c=144-6x=36
c=6
ans:
rate of speed of boat in still water=18 mph
rate of speed of current=6 mph

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water
-----------
Speed d/s = 72/3 = 24 mi/hr
Speed u/s = 60/6 = 10 mi/hr
---
The boat's speed is the average = 17 mi/hr
The current is the difference = 7 mi/hr