SOLUTION: It takes 10 hours to fill a pool with water, and 20 hours to drain it. If the pool is empty, and the drain is open, how long will it take to fill the pool?

Algebra ->  Human-and-algebraic-language -> SOLUTION: It takes 10 hours to fill a pool with water, and 20 hours to drain it. If the pool is empty, and the drain is open, how long will it take to fill the pool?      Log On


   

Question 33703This question is from textbook algebra 1
: It takes 10 hours to fill a pool with water, and 20 hours to drain it. If the pool is empty, and the drain is open, how long will it take to fill the pool? This question is from textbook algebra 1

Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
water in - water out = 1pool
in: 10 hours 1/10 hours together -->x part done is hours x/10
out: 20 hours 1/20 hours together -->x Part done is hours x/20
Equation:
x%2F10-x%2F20=1
Multiply the whole equation by 20:
20%28x%2F10%29-20%28x%2F20%29=20%281%2F1%29
2x-x=20
x=20
Hence, it will take 20 hours to fill the pool.
Paul.