Answer:
The total cost of the rocks needed for the border is $538.80.
Step-by-step explanation:
The length of the lawn is = 150 feet
The width of the lawn is = 80 feet
The gravel border will be 6 feet wide from all sides.
So, bigger rectangle will have length = feet
And width will be = feet
Area of the bigger rectangle = square feet
Area of the smaller rectangle = square feet
So, area of the gravel area will be = square feet.
Now depth of gravel is 2 inches. So, volume will be area of gravel times depth.
We will convert 2 inches in feet.
12 inches = 1 feet
So, 2 inches = feet
cubic feet
1 cubic foot = 0.037037 cubic yard
So, 484.97 cubic feet = cubic yards
Now cost of gravel per cubic yard is $30.
So, total cost will be = dollars
Therefore, the total cost of the rocks needed for the border is $538.80.
Please find attached the diagram of the lawn.