SOLUTION: Rita rows 12 km upstream and 12 km downstream in 3 hours. The speed of her boat in still water is 9 km/hr. Find the speed of the stream.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Rita rows 12 km upstream and 12 km downstream in 3 hours. The speed of her boat in still water is 9 km/hr. Find the speed of the stream.      Log On


   

Question 40652This question is from textbook
: Rita rows 12 km upstream and 12 km downstream in 3 hours. The speed of her boat in still water is 9 km/hr. Find the speed of the stream. This question is from textbook

Answer by checkley71(8403) About Me  (Show Source):
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12/(9+X)+12/(9-x)=3 OR 12(9-X)+12(9-X)/(9+X)(9-X)=3 OR (108+12X+108-12X)/(9-X)(9+X)=3 OR 216/(9-X)(9+X)=3 OR 2168=3(81-X~2) OR 216=243-3X~2 OR -27=-3X~2 OR
X~2=9 OR X=3 THEREFORE THE CURRENT IS 3 MPH
PROOF 12/(9-3)+12/(9+3)=3 OR 12/6+12/12=3 OR 2+1=3 OR 3=3