1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Differential Equations

  1. May 25, 2008 #1
    An acid solution flows at a constant rate of 6L/min into a tank which initially holds 200L of a 0.5% acid solution. The solution in the tank is kept well mixed and flows out of the tank at 8L/min. If the solution entering the tank is 20% acid then determine the volume of acid in the tank after t minutes.

    I just want to make sure I have the differential equation right.
    let y(t) be the amount of acid solution in the tank.
    rate in = 0.2 * 6 = 1.2L acid per min
    rate out = y(t)/v(t) * 8, where v(t) = 200 - 2t is the volume of liquid in the tank

    So I got

    \frac{dy}{dt} + \frac{8}{200-2t}y=1.2

    Can someone please confirm that this is the right equation to be working with?
  2. jcsd
  3. May 25, 2008 #2


    User Avatar
    Science Advisor

    Yes, that is correct.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook