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Virtual Math Learning Center

Virtual Math Learning Center Texas A&M University Virtual Math Learning Center

MATH 308 WIR22A V3

Author: Kamran Reihani

The following problem is solved in this video. It is recommended that you try to solve the problem before watching the video. You can click "Answer" to reveal the answer to the problem.

Problem: Your swimming pool containing 60,000 gal of water has been contaminated by 5 kg of a non toxic dye that leaves a swimmer's skin an unattractive green. The pool's filtering system can take water from the pool, remove the dye, and return the water to the pool at a flow rate of 200 gal/min.

  1. Write down the initial value problem for the filtering process; let \(q(t)\) be the amount of dye in the pool at any time \(t\).
  2. Solve the problem.
  3. You have invited several dozen friends to a pool party that is scheduled to begin in 4 hours. You have also determined that the effect of the dye is imperceptible if its concentration is less than 0.02 g/gal. Is your filtering system capable of reducing the dye concentration to this level within 4 hours?

  1. \(\dfrac{dq}{dt}=-\dfrac{1}{300}q(t),\quad\)\(q(0)=5\)
  2. \(q(t)=5e^{-\frac{1}{300}t}\)
  3. Four hours is not enough time.

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