Thinking spatially is not a strength of mine. This may require another cup of coffee. lol Ok, yes, that's the cubic yards, but to convert that to tons we need to multiply by 1.4.

ok, volume of a rectangular prism=LxWxH, right?
24x28x.75=504 cf (The .75 is 9/12 inches since we're working with feet)

To convert the cubic ft to cubic yds we divide by 27, and we get 18.666.

The weight of pea gravel per cubic yard is appx 1.4 tons, (and I'm seeing that figure in multiple places so I assume it's correct), so we get 26.1333 tons.

I know we must have someone here who's a math wiz- am I making a mistake somewhere?