(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The air in a small room 12x8x8 ft (768 ft^3 is the volume) is 3% carbon monoxide. Starting at t=0, fresh air containing no carbon monoxide is blown into the root at rate of 100 ft^3/min. If the air in the room flows out at same rate (100 ft^3/min), when will air in room be 0.01%?

2. Relevant equations

s'(t) = (rate entering)(concentration entering) - (rate exiting)(concentration exiting)

concentration = amount/volume

3. The attempt at a solution

I don't need you to solve the problem for me, but I am having trouble getting started and figuring out what the concentration is.

s'(t) = (rate entering)(concentration entering) - (rate exiting)(concentration exiting)

s'(t) = (100)(?) - (100)(?)

concentration = amount/volume

Since it said at time t=0, fresh air containing *NO* carbon monoxide..., will the concentration entering be 0?

And for the concentration exiting, will it be s(t)/768?

so the s'(t) is: 0 - 100s(t)/768

Is this correct?

I am contemplating about the 3% carbon monoxide, could this be the concentration entering??

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# Homework Help: Differential Equation: Mixing Problem

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