SOLUTION: I hope this is the title this problem should be under. I have a question on a word problem below 1. A boat takes 3hrs to go 24 miles upstream. It can go 36 miles downstream in t

Algebra ->  Expressions -> SOLUTION: I hope this is the title this problem should be under. I have a question on a word problem below 1. A boat takes 3hrs to go 24 miles upstream. It can go 36 miles downstream in t      Log On


   

Question 32565: I hope this is the title this problem should be under. I have a question on a word problem below
1. A boat takes 3hrs to go 24 miles upstream. It can go 36 miles downstream in the same time. Find the speed of the boat (still water) and the speed of the current. bonus: how far downstream does a styrofoam cup float in 3 hours?
- I know I need to set it up with x= something and y= something but I can't figure out what goes where.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Let the speed of the boat in still water be "b".
Let the speed of the stream be "s".
UPSTREAM DATA:
distance=24 mi time= 3 hr. therefore rate= b-s=24/3=8
DOWNSTREAM DATA:
distance=36 mi time= 3 hr. therefore rate= b+s=36/3=12
EQUATION:
b-s=8
b+s=12
Add the equations to get 2b=20
Then b=10 mph (speed of boat in still water)
Substitute to get "s"
10+s=12
Then s=2 mph (speed of the stream)
Cheers,
Stan H.