Calculus- area of a garden problem

[cinematic]

Homework Statement

A rectangular rose garden will be surrounded by a brick wall on three sides and a fence on the fourth side. The area of the garden will be 1000m². The cost of the brick wall is $192/m. The cost of the fencing is $48/m. Find the dimensions of the garden so that the cost is a minimum. [domain and test not needed]

Homework Equations

So I know A = 1000m² and A=lw

The Attempt at a Solution

My question is, how do I do this when the sides are different due to the materials used in building them? It's not like a question where you fence in three sides with the same stuff and just optimize costs...I'm very slow at calculus, please explain details! I really appreciate this.

 

[LCKurtz]

You want to think about the perimeter and its cost. Start by writing a formula for the cost:

Cost = some function of L and W.

That's what you want to minimize.