A carpenter has been asked to build an open box with a square base. The sides of the box will cost $3 per square meter and the base will cost $4 per square meter. What are the dimensins of the box of greatest volume that can be constructed for $48?

Should I start with finding the Surface Area or the Volume?

I'm not sure if I remember the formulas:

SA = 2b^2 + 4bh

V = b^2h