SOLUTION: Problem: It take 5.5 hours to go 2 miles upstream against the current. It can go 9 miles downstream in the same amount of time.Find the speed of the boat in still water and speed o

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Question 373485: Problem: It take 5.5 hours to go 2 miles upstream against the current. It can go 9 miles downstream in the same amount of time.Find the speed of the boat in still water and speed of current.Simplify your answer.
Here is how far I can get and then I get stuck
5.5p + 5.5w = 9
5.5p - 5.5w = 2

5.5p = 18
5.5p = 18
____ ___
5.5 5.5
p = a fraction
Normally you would divide the 18 by 5.5 but it does not go evenly and it is a continious decimal and it is asking for the answer in fraction form. What I can not figure out is how they are getting this in to correct (answer) fraction form as well as when figuring the fraction form for w variable
I know that you are suppose to solve the w variable this but again I am having trouble understanding how they are solving with fractions
(5.5)times the fraction from p variable + 5.5 = 9
5.5w = 2
w = a fraction
Can you please help
Thank you for your time it is truly appreciated!
Jaimee

Answer by josmiceli(9669) (Show Source):
You can put this solution on YOUR website!
Let = the speed of the boat with no current
Let = the speed of the current
= speed of boat going against current
= speed of boat going with the current
-------------------
given:

Now you can just add these equations

and, since

The boat in still water goes 1 mi/hr
The speed of the current is 7/11 mi/hr
check answer:

and

OK