#12 material used ??

[Kristy]

Problem
Number 12 A rectangular storage container with an open top is to have
a volume of 10 m^3
The length lf its base is twice the width
Material for the base costs $10 per square meter
Material for the sides costs $6 per square meter
Find the cost of materials for the cheapest such container

My work, or being confused:

first, what’s the answer want? Just a dollar amount? or do they want the length, width, and height? Or something else?

length = 2 * widdth

Volume = y * 2w * w
Volume = y * 2w^2

 

[skeeter]

Problem
Number 12 A rectangular storage container with an open top is to have
a volume of 10 m^3
The length lf its base is twice the width
Material for the base costs $10 per square meter
Material for the sides costs $6 per square meter
Find the cost of materials for the cheapest such container

My work, or being confused:

first, what’s the answer want? Just a dollar amount? or do they want the length, width, and height? Or something else? read the above statement ... seems clear what "they" want.

length = 2 * widdth

Volume = y * 2w * w
Volume = y * 2w^2

2w²y = 10
y = 5/w²

cost = $10(base area) + $5(lateral area)

C = 10(2w²) + 5(6wy)

C = 20w² + 150/w

now find the value of w that minimizes the cost, C.