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Pretty simple optimization problem

  1. May 10, 2009 #1
    A closed box with a square base is to contain 252ft^3. The bottom costs 5$ per ft.^2, the top is 2$ft^2 and the sides cost 3$ft^2. Find the dimensions that will minimize the cost.

    As for equations we have v=lwh and I'm not sure as to how to find the next relative equation.

    I just need to find another formula so I can derive and solve. Any help is much appreciated.
  2. jcsd
  3. May 10, 2009 #2
    What are the areas of the different sections?
  4. May 10, 2009 #3
    It doesnt say, thats directly quoted from the text.
    i wanna say its something like
    3(lw)=sides 5(lw)-bottom 2(lw)-top
  5. May 10, 2009 #4
    That was meant to be a hint for your next equation. Calculate the areas and you can work out the cost from that. Note that there are only two free parameters since the bottom is a square.
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