SOLUTION: Pipe A can fill the pool in 3 hours and pipe B can drain it in 6 hours. The caretaker opens pipe A at 6:00 every morning. One day, 30 minutes after opening the pipe, he noticed tha

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Pipe A can fill the pool in 3 hours and pipe B can drain it in 6 hours. The caretaker opens pipe A at 6:00 every morning. One day, 30 minutes after opening the pipe, he noticed tha      Log On


   

Question 1032764: Pipe A can fill the pool in 3 hours and pipe B can drain it in 6 hours. The caretaker opens pipe A at 6:00 every morning. One day, 30 minutes after opening the pipe, he noticed that both pipes were open and he immediately closed pipe B. What time will the pool be filled with water?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Pipe A can fill the pool in 3 hours
It does 1/3 of the job in 1 hour

and pipe B can drain it in 6 hours.
It does 1/6of draining job in 1 hour


The caretaker opens pipe A at 6:00 every morning.
For 1/2 hour both were open.
In 1 hour 1/3 -1/6 of the job of filling is done
=1/6
In 1/2 hour
1/6*1/2 = 1/12 of filling is done
Balance filling will be 1-1/12 = 11/12
Filling
It does 1/3 of job in 1 hour
so 11/12 of the job it will take
11/4 hours
Pool will get filled in 1/2 + 11/4 = 13/4 hours
3.25 hours
The pool will fill at 9:15 AM