SOLUTION: Traveling by boat. Alonzo can travel from his camp downstream to the mouth of the river in 30 minutes. If it takes him 45 minutes to come back, then how long would it take him to g

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Question 715283: Traveling by boat. Alonzo can travel from his camp downstream to the mouth of the river in 30 minutes. If it takes him 45 minutes to come back, then how long would it take him to go that same distance in the lake with no current?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
let the distance be d
d=rt
d/t = r
d/(1/2) = r
r=2d ( downstream)

d/(3/4) = r
4d/3 = r upstream

let speed of boat in still water be b
and speed of current be c
b+c =2d
b-c= 4d/3
add up
2b= 10d/3
b= 5d/3 speed of boat in still water

in lake water t= d/r
t= d/(5d/3)
=3/5 hour
if you want to convert to minutes multiply by 60