Optimazation prob: landscaper is creating rectangular garden

[kimmy_koo51]

A landscape architect is creating a rectangular rose garden in a local park. The rose garden is to have an area of 60 m^2 and be surrounded by a lawn. The surrounding lawn is to be 10m wide on the north and south sides of the rose garden, and 3 m wide on the east and west sides. Find the dimensions of the rose garden if the total area of the garden and lawn together is to be a minimum.

I have nothing for this one.

 

[skeeter]

let x = east/west length of garden
y = north/south length of garden

area of the garden is 60 m² ...
xy = 60

area of the garden + lawn ...
A = (x+6)(y+20)

get the area equation in terms of a single variable, find the derivative, and minimize.