SOLUTION: A motorbat can travel 9 miles/hr up a river and back downstream at 15 miles/hr. Find the rate of motorbat in still water and the rate of the river current.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: A motorbat can travel 9 miles/hr up a river and back downstream at 15 miles/hr. Find the rate of motorbat in still water and the rate of the river current.      Log On


   

Question 1066862: A motorbat can travel 9 miles/hr up a river and back downstream at 15 miles/hr. Find the rate of motorbat in still water and the rate of the river current.
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39621) About Me  (Show Source):
You can put this solution on YOUR website!
Is the trip up the same distance as the trip back down?

9%2Au=15%2Ab for uP and bACK times

system%289=r-c%2C15=r%2Bc%29 for r rate if no current, c for rate of just the current - this is the system needed.

ELIMINATION METHOD
Add corresponding members.
%28r-c%29%2B%28r%2Bc%29=9%2B15
r-c%2Br%2Bc=24
2r=24
highlight%28r=12%29------boat speed in still water.
-
Subtract corresponding members.
%28r%2Bc%29-%28r-c%29=15-9
2c=6
highlight%28c=3%29------speed of the river current

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

A motorbat can travel 9 miles/hr up a river and back downstream at 15 miles/hr. Find the rate of motorbat in still water and the rate of the river current.


It's as simple as that...nothing COMPLEX and/or CONFUSING!