Wow, negative weights! Crazy
Correct me if I'm wrong, but didn't some famous guy roll various things with a different masses/densities down a ramp, and drop them off a building, and discovered that stuff falls the same speed no matter how heavy/light/dense it is (as long as wind resistance doesn't count)?
So, unless you want to calculate wind resistance, they should get there at the same time.
If you DO want to use wind resistance, then the solid one will, because having a hole in the hollow one will create drag.
Of course, maybe there's some totally other explanation. But I don't see how this case would be any different from the orange/bowling ball..