# Math Help - [SOLVED] Optmization - Cost

1. ## [SOLVED] Optmization - Cost

Question: A rectangular storage container is to have a volume of 10 meters cubed. The length of the base is twice the width. Material for the base costs $10 per square meter. Material for the sides and top costs$6 per square meter. Find the cost of the materials for the cheapest such container. ANS: \$191.28

So I have $A = 40w^2 + 36wh$ and $V = 2w^2h$

Then rearranging V to get $h = 10/2w^2$

What am I doing incorrectly? I subbed h into the A equation and solved dA/Dw equal to zero. . . $0 = 80w - 180w/w^2$

I got w = 1.5 and h = 20/9

2. Never mind, I figured this out...