It depends how thick the gravel is being laid - at 4 inches thick, a cubic yard will cover 81 square feet.
You will need about 3.7 cubic yards (around 4.75 tons) of gravel.
I need to know how thick the layer of gravel is meant to be.
3 yards of 2in prewashed river rock
That depends on the size of the gravel and how thick a layer you want to end up with.
It would take roughly 66 bags to cover a 200 square ft area 2 inches thick
You have not said what substance you are using a ton of to cover the asphalt.
One "yard" of dirt (meaning one cubic yard) contains 46,656 cubic inches. Spread 8 inches thick this will cover 5832 square inches or 40.5 square feet.
The amount of gravel needed to cover 252 square feet depends on how thick (that is, deep) you want the gravel. If you want the gravel to be 3 inches thick... Convert the measurement to the same units. We'll use feet. 3 inches = 1/4 foot Multiply the thickness times the area to get volume in cubic measure. 1/4 feet x 252 feet = 63 cubic feet Gravel in the US is usually sold by the cubic yard, which is 27 cubic feet Thus, 63/27 = 2 1/3 cubic yards 2 1/3 cubic yards of gravel will cover 252 square feet of area to a dept of 3 inches.
Approx 70.6 square feet.
One yard will cover 81 square feet 4 inches thick, So 81x40=3,240 square feet if spread 4 inches thick. 36/4=9, 9x3x3=81, 81x40=3,240 If you want it 6 inches thick 36/6=6, 6x3x3=54, So one yard will cover 54 square feet 6 inches thick, And 54x40=2,160 square feet If spread 6 inches thick! Now this is spreading it on thick/DEEP!
540 square feet