Question

will give a great medal *** An aquarium with a square base has no top. There is a metal frame. Glass costs 3 dollars/m^2 and the frame costs 10 dollars/m. The volume is to be 20 m^3. Express the total cost C in terms of the height h in meters. (Hint: work out the cost of the glass and frame separately.)

Answer 1

20/h = A of base

sqrt(20/h) = L

4*sqrt(20/h) = Perimeter of base

h*4 = sum of sides

4*sqrt(20/h) = Perimeter of top

8*sqrt(20/h) + 4h = Sum of all twelve sides

10*(8*sqrt(20/h) + 4h) = 80sqrt(20/h) + 40h = Cost of entire metal frame

3*(4*h*sqrt(20/h) + (20/h))= Cost of glass

80sqrt(20/h) + 40h + 3*(4*sqrt(20h) + (20/h))= C

Answer 2

got it? @butterflyprincess