Answer:
The value is 
Step-by-step explanation:
From the question we are told that
The area of the rectangular pen is 
The cost of material used to make one side is 
The cost of material used to make the other sides is 
Now , the fence to be build around the rectangular pen has four sides, the first opposite sides are equal, let assume each of the to be x yard and the other opposite sides are also equal as well let assume of the to be y yard
So the cost is mathematically represented as

=> 
=> 
Now the area of the fence is mathematically represented as

=> 
=> ![C = 9x + 6[\frac{24}{x} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209x%20%20%2B%20%206%5B%5Cfrac%7B24%7D%7Bx%7D%20%5D)
=> ![C = 9x + [\frac{144}{x} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209x%20%20%2B%20%20%5B%5Cfrac%7B144%7D%7Bx%7D%20%5D)
Now differentiating


At minimum 
So




Now substituting for x in the equation above to obtain minimum cost
![C = 9(5.66) + [\frac{144}{5.66} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209%285.66%29%20%20%2B%20%20%5B%5Cfrac%7B144%7D%7B5.66%7D%20%5D)

Answer:
They can bike 7.2 miles in 30 minutes.
Step-by-step explanation:
2.4 * 3 = 7.2
1 week = 7 days
10 weeks = 10×7 days
= 70 days
if Ellen reads 1 book in a day
Therefore,
1 day = 1 book
70 days = 70×1
= 70 books.
Thus Ellen reads 70 books in 10 weeks.
Hope helps
Divide $71,000 by 24 because there are 12 months in a year and he gets paid 2 times a month. I got $2,958.33