Answer:
150 feet by 300 feet.
Step-by-step explanation:
The fence is to enclose a rectangular area of 45,000 ft squared.
If the dimensions of the rectangle are x and y
Area of a rectangle = xy
- xy=45000

Perimeter of the Rectangle =2x+2y
Fencing material costs $ 3 per foot for the two sides facing north and south and $6 per foot for the other two sides.
- Cost of Fencing, C=$(6*2x+3*2y)=$(12x+6y)
Substitute
into the Cost to get C(y)
C=12x+6y

The value at which the cost is least expensive is at the minimum point of C(y), when the derivative is zero.


Recall,

Since x=150, y=300
The dimensions that will be least expensive to build is 150 feet by 300 feet.
Remember that when you find 30% of the number you have to subtract the 30% from your original $90 because it is 30% off the original price.
The answer is no. No matter how you do it two mixed numbers will never be a whole and even 2
Take a better picture, so we can actually see the work?