SOLUTION: One pipe fills a storage pond in 20 hours. A second pipe fills the same pond in 15 hours. When a third pipe is added and all three are used at fill the pond, it takes only 6 hours.

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: One pipe fills a storage pond in 20 hours. A second pipe fills the same pond in 15 hours. When a third pipe is added and all three are used at fill the pond, it takes only 6 hours.      Log On


   

Question 31095This question is from textbook Prealgebra and Introductory Algebra
: One pipe fills a storage pond in 20 hours. A second pipe fills the same pond in 15 hours. When a third pipe is added and all three are used at fill the pond, it takes only 6 hours. Find how long it would take the third pipe alone to do the job. This question is from textbook Prealgebra and Introductory Algebra

Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Let x be the time:
Equation:
1%2F20%2B1%2F15%2B1%2Fx=1%2F6
Multply the whole equation by 60:
60%281%2F20%29%2B60%281%2F15%29%2B60%281%2Fx%29=60%281%2F6%29
3%2B4%2B60%2Fx=10
3x+4x+60=10x
7x+60=10x
3x=60
x=20

Hence, it would take the pipe 20 hours to do it alone.
Paul.