The dimensions of the rectangular pen should be 15 by 20 feet and the maximum area is 1200 square feet.
Let the area be y .
Area = (base) × (height)
Base = 2x
Height = h
Let the area of the rectangular pens be y .
∴ y = 2xh
Perimeter of all the fencing = 4x+3h
∴ 4x+3h = 120
now we solve for h
3h = 120-4x
h = 40 - 4/3 x
Now we will substitute this value in the above first equation:
y = 2xh
or, y = 2x (40 - 4/3 x)
or, y = 80x - 8/3 x²
Now for the maximum area we have to find the first order differentiation of y
now,
dy /dx = 80 - 16/3 x
At dy/dx = 0 we get the value of x for which y is maximum.
80 - 16/3 x = 0
or, - 16/3 x = -80
or, x = 15 feet
Hence height = 40 - 4/3 x = 40 - 20 = 20feet
Maximum area = 2xh = 2×15×40 = 1200 square feet
The dimensions of the rectangular pen should be 15 by 20 feet and the maximum area is 1200 square feet.
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1300+22=1322 1322+6=1328 answer: 1328
Answer:
You will break even on the car wash when you buy 13.5 gallons. As long as you buy that or more, it is cheaper to get the car wash.
Step-by-step explanation:
In order to find this, we need to create equations for both situations. If we let x equal the amount of gallons purchased, we can model the first equation as:
f(x) = 3.35x
And the second equation as:
f(x) = 3.05x + 4.05
Then to find when they equal each other, we can set the two equations equal to each other and solve for x.
3.35x = 3.05x + 4.05
0.30x = 4.05
x = 13.5
This means once you buy 13.5 gallons, the prices will be the same. Any amount over that and the car wash will be cheaper