# Math Help - minimizing the cost of making a box with an open top

1. ## minimizing the cost of making a box with an open top

a box is made with a square bottom and open top to hold a volume of 8ft3. the material for the sides cost $4 per square foot and the material for the bottom costs$1 per square foot. What dimensions will minimize the cost of the box?

2. ## Re: minimizing the cost of making a box with an open top

what equations have you come up with from the given problem statement?

3. ## Re: minimizing the cost of making a box with an open top

Let "x" be the length of each side of the base and "y" be the height. What is the volume in terms of x and y? What is the total area in terms of x and y?

4. ## Re: minimizing the cost of making a box with an open top

how do you solve a volume with 2 variables???

5. ## Re: minimizing the cost of making a box with an open top

Originally Posted by OceanicBlue
how do you solve a volume with 2 variables???
you come up with two equations ... the object equation (cost) and constraint equation (volume).