# Thread: A problem on pipes and tank

1. ## A problem on pipes and tank

Need help to solve algebra 1 homework problem

Two pipes can fill a tank in 24min and 32 min respectively. If both the pipes are function simultaneously, after how much time the second pipe should be closed, so that the tank is full in 18 minutes?

Thanks

2. ## Re: A problem on pipes and tank

Whenever two or more thing "work together" (pipes filling a tank, pipes emptying a tank, people or machines doing a job, etc.), their rates of work add.

Here you are told that one pipe can fill the tank in 24 minutes so its rate is 1/24 "tank per minute". The other pipe can fill the tank in 32 min so its rate is 1/32 "tank per minute". The two pipes together fill the tank at 1/24+ 1/32 "tank per minute".

Here, you have both tanks working for, say, t minutes then the first pipe only for (18- t) minutes to fill the tank. So that is (1/24+ 1/32)t+ (1/24)(18- t)= 1 (tank). Solve that equation for t.

3. ## Re: A problem on pipes and tank

Thank you for your detailed explanation!!!

Originally Posted by HallsofIvy
Whenever two or more thing "work together" (pipes filling a tank, pipes emptying a tank, people or machines doing a job, etc.), their rates of work add.

Here you are told that one pipe can fill the tank in 24 minutes so its rate is 1/24 "tank per minute". The other pipe can fill the tank in 32 min so its rate is 1/32 "tank per minute". The two pipes together fill the tank at 1/24+ 1/32 "tank per minute".

Here, you have both tanks working for, say, t minutes then the first pipe only for (18- t) minutes to fill the tank. So that is (1/24+ 1/32)t+ (1/24)(18- t)= 1 (tank). Solve that equation for t.