Errol Groff wrote:

A cubic yard is 27 cubic feet. 3*3*3 = 37

So 200/27 is 8 yards of gravel

If the stone yard/mill/mine sells by weight, you will need about 10-10.5
tons.

8 yards times 2600# per yard equals 20,800# or 10.5 tons.
(based on the weight of crush and run limestone).