SOLUTION: Latoya's boat has a top speed of 20 mph in still water. While traveling on a river at top speed, she went 40 miles upstream in the same amount of time she went 60 miles downstream.

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Latoya's boat has a top speed of 20 mph in still water. While traveling on a river at top speed, she went 40 miles upstream in the same amount of time she went 60 miles downstream.      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1057002: Latoya's boat has a top speed of 20 mph in still water. While traveling on a river at top speed, she went 40 miles upstream in the same amount of time she went 60 miles downstream. Find the rate of the river current.
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
               SPEED         TIME        DISTANCE
UPSTRM         r-c           t           u
DOWNSTRM       r+c           t           d

system%28r=40%2Cu=40%2Cd=60%29
The rule for constant travel rate is RT=D.

You know what to do. Right?

Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
.
Latoya's boat has a top speed of 20 mph in still water. While traveling on a river at top speed, she went 40 miles upstream
in the same amount of time she went 60 miles downstream. Find the rate of the river current.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

Let "v" be the rate of the river current.

Then the speed of the boat upstream is 20-v mph,
while its speed downstream is 20+v mph.

The condition says 

40%2F%2820-v%29 = 60%2F%2820%2Bv%29.

It is yours governing equation. 
To solve it, multiply both sides by (20-v)*(20+v). You will get

40*(20+v) = 60*(20-v),   or

800 + 40v = 1200 - 60v,

40v + 60v = 1200 - 800,

100v = 400,

v = 4.

Answer. The rate of the river current is 4 mph.