Answer:
12 trips
Step-by-step explanation:
Given;
Dimension of cone shapef pile of earth;
height h = 12 ft = 4 yards
diameter d = 30 ft = 10 yards
radius r = d/2 = 10/2 = 5 yards
The volume of a cone V;
V = (1/3)πr^2 h
Substituting the given values;
V = (1/3) ×π × 5^2 × 4 cubic yards
V = 104.72 cubic yards
Given that a dump truck have a capacity of 9 cubic yards.
Vc = 9 cubic yards
Number of trips it will take is;
N = Volume of earth pile/truck capacity
N = V/Vc
Substituting the values;
N = 104.72/9
N = 11.64
N ≈ 12 trips
Therefore, the truck will make 12 trips
