N x 2 = 12 + 5n
2n - 5n = 12
-3n = 12
3n = -12
n = -4
Answer:
13.125 cubic inches
Step-by-step explanation:
Volume of box is 3/2 X 7/2 X 5/2 = 105/8 = 13 1/8 = 13.125 cubic inches
Answer:



Step-by-step explanation:
Given




Required
The dimension that minimizes the cost
The volume is:

This gives:

Substitute 


Make H the subject


The surface area is:
Area = Area of Bottom + Area of Sides
So, we have:

The cost is:



Substitute:
and 



To minimize the cost, we differentiate

Then set to 0


Rewrite as:

Divide both sides by W

Rewrite as:

Solve for 


Take cube roots

Recall that:







Hence, the dimension that minimizes the cost is:



(3x^2 - 5x +3) + (-2x -3x)
=3x^2-5x+3 + (6x^2)
=9x^2-5x+3