Speed of any freely falling object is always same. Provided, both are left to fall from the same height. If you perform this experiment in a perfect vacuum or near vacuum laboratory, both of them will reach ground with same velocity this is because there is no resistance to their motion. This is always true no matter where you go and perform this experiment.
It can be easily proved from conservation of mechanical energy. Why conserving energy? because there are no forces acting on the freely falling objects other than conservative force(mg).
It weakened the gravitational force between the oblects.
In order to find the solid, you would want the object in which sound travels the fastest
In this case, since in object C, the speed of sound is the fastest, it is the most likely to be a solid
So object C is most likely to be a solid
The jetliner is traveling against the wind. The net speed of the jetliner is
590 mph - 36 mph = 554 mph
The time it takes for the jetliner to arrive at the destination is
1850 miles / 554 mph = 3.34 hours