## anonymous one year ago A rectangular storage container with an open top is to have a volume of 12 cubic meters. The length of its base is twice the width. Material for the base costs 15 dollars per square meter. Material for the sides costs 7 dollars per square meter. Find the cost of materials for the cheapest such container.

1. Itsyacoolgrl

Is it a multiple choice question?

2. anonymous

No

3. Itsyacoolgrl

oh ok

4. alekos

tough question have they given you an answer?

5. anonymous

They have not no

6. Rizags

make a cubic for it

7. Rizags

first write the length width and height in terms of "w"

8. alekos

i have a solution but i'll have to get back to you @rburns4

9. anonymous

Ok @alekos

10. alekos

sorry i have to go. i can go through the full solution at another time. when would suit you?

11. anonymous

I need it by tonight because it is due tomorrow and I will be busy

12. alekos

what time is it where you are?

13. anonymous

Arizona time it's noon now

14. anonymous

|dw:1434739818457:dw|

15. anonymous

How do you minimize something? @peachpi

16. anonymous

Take the derivative and find the x values where it is 0.

17. anonymous

then test them with either the 1st or 2nd derivative test

18. anonymous

finding the x value where it is zero is just making it equal to zero right? @peachpi

19. anonymous

make the derivative 0 and solve for x. $C'(x) = 60x-\frac{ 7 }{ x^2 }=0$

20. alekos

here is the solution. peachpi's method is correct but the numbers are wrong.

21. anonymous

RE alekos' solution: The 4 sides don't have the same area. 2 of them have area hx and 2 of them have area 2hx.

22. alekos

yes you're right. thanks peachpi. total area of the sides is 6hx which works out to 252/x. I get x=1.613 for a minimum cost of $234. @peachpi can you please check my answer 23. anonymous yes that's right. 24. alekos thanks 25. anonymous It says that is is wrong @alekos 26. anonymous try$234.28

27. alekos

@rburns, What says that it's wrong? Answer should be as peachpi has written and verified by the two of us