Want this question answered?
The answer depends on the depth to which the area is covered and, to some extent, that will depend on the size of the gravel.
242 cubic feet
You'll need about 28.704 cubic yards (37 tons) of gravel.
You will need about 463 cubic yards (around 594 tons) of gravel for this area.
I need to know how thick the layer of gravel is meant to be.
You will need about 3.7 cubic yards (around 4.75 tons) of gravel.
You would need about 13 cu yards or about 15 tons.
Approximately 24.7 cubic yards or 31.7 tons of gravel.
The answer depends on the depth to which the area is covered and, to some extent, that will depend on the size of the gravel.
242 cubic feet
You'll need about 28.704 cubic yards (37 tons) of gravel.
You will need about 463 cubic yards (around 594 tons) of gravel for this area.
I need to know how thick the layer of gravel is meant to be.
That's not enough information. You need to know the width of the trench, and how much volume 1 ton of gravel is equivalent to.
1 square km of gravel
Depends on depth of gravel you plan to put down. For each 1 inch depth: Estimate gravel having a density of 2.7. 150 x 1/12 x 62.4 x 2.7 = 2106 pounds (slightly more than 1 ton) so if you want 3 inches of gravel you need about 3 tons of gravel
1 cement 2 sand 3 gravel