Answer:
y ≥ 4x
y ≤ 8.75 –1/2πx^2
Step-by-step explanation:
Because the diameters of the gravel bases added together cannot exceed the width of the pen, we get the inequality 2x + 2x ≤ y . Rewriting, we get y ≥ 4x as the first inequality in the system.
Next, write an inequality for cost.
To write the expression for the cost of the fencing, find the perimeter of the rectangle, and multiply the perimeter by the cost per foot of fencing. The pen is a rectangle, so the perimeter is 2(10) + 2(y), or 20 + 2y. Multiply the cost of the fencing material ($4.00 per foot) by the perimeter of the fence to get 4(20 + 2y).
Now, write an expression for the gravel bases for the circular food containers. Because A = r2 and the cost of the gravel is $2.00 per square foot, multiply the cost of the material by the sum of these areas to get 2(x2) + 2(x2).
The total cost must be less than or equal to $150. So, we can say that 4(20 + 2y) + 2(x2) + 2(x2) ≤ 150. After simplifying and solving for y: y ≤ 8.75 – x2.
So, this is the system:
y ≥ 4x
y ≤ 8.75 –1/2πx^2
