heheheheh - no disrespect Lbear... but 1/360x24' = 0.8" when loaded to max.
jokes aside
you would have to provide at least the Live Load and the rebar in beams...
For a 24' span - I think a couple of #6 bars would do the job just fine for up to 60psf LL at 300psi mix. Maybe keep the slab to 3" max to keep the DL down. Unless you have big big point loads such as cars
if all else fails consider a oh lets say 1/2" camber... super easy to shore it up this way...