trick problem? Consider a saltwater fish tank that contains 200L of saltwater....

[dmacias2012]

Consider a saltwater fish tank that contains 200L of saltwater. Suppose that there are initially 100 grams of salt dissolved in this water (so a salinity of .5 grams per liter). I need to slowly increase the salinity so implement the following procedure:

i. Install a pump to remove fully mixed saltwater at a rate of 5 liters per minute from the tank;
ii. Install a second pump to replenish the tank with 5 liters of saltwater per minute, with salinity of 1 gram per liter.

Answer the following questions in data given above.

How long will it take for the tank to reach a salinity of 1.5 grams of salt per liter? [please indicate clearly what the differential equation you solved to answer this question.]

What will the salinity of the water be in the very long run if I let the procedure continue unimpeded?

 

[stapel]

Consider a saltwater fish tank that contains 200L of saltwater. Suppose that there are initially 100 grams of salt dissolved in this water (so a salinity of .5 grams per liter). I need to slowly increase the salinity so implement the following procedure:

i. Install a pump to remove fully mixed saltwater at a rate of 5 liters per minute from the tank;
ii. Install a second pump to replenish the tank with 5 liters of saltwater per minute, with salinity of 1 gram per liter.

Answer the following questions in data given above.

How long will it take for the tank to reach a salinity of 1.5 grams of salt per liter? [please indicate clearly what the differential equation you solved to answer this question.]

What will the salinity of the water be in the very long run if I let the procedure continue unimpeded?

Since it seems you are unable even to get started, the first thing to do is study some lessons, so you can learn the basic terms and techniques for this sort of exercise. I've found some links which should be helpful.

. . . . .Paul's Online Math Notes: Modelling
. . . . .Mixing-Tank Separable Diff-EQ Examples
. . . . .Mixture Problems (starting on pg 14)
. . . . .Mixing Problems (starting on pg 5)
. . . . .Applications: Mixing Problems
. . . . .Physics Forums: discussion

Once you have studied the content provided at at least three of the links, please attempt the exercise. If you get stuck, you can then reply with a clear listing of your thoughts and efforts, at which point we can begin to work with you. Thank you!

 

[dmacias2012]

Since it seems you are unable even to get started, the first thing to do is study some lessons, so you can learn the basic terms and techniques for this sort of exercise. I've found some links which should be helpful.

. . . . .Paul's Online Math Notes: Modelling
. . . . .Mixing-Tank Separable Diff-EQ Examples
. . . . .Mixture Problems (starting on pg 14)
. . . . .Mixing Problems (starting on pg 5)
. . . . .Applications: Mixing Problems
. . . . .Physics Forums: discussion

Once you have studied the content provided at at least three of the links, please attempt the exercise. If you get stuck, you can then reply with a clear listing of your thoughts and efforts, at which point we can begin to work with you. Thank you!

I just don't know how to see it up in order to get the time at which it is 1.5. I know how to st it up to know what the concentration is after a certain amount of time.