Question

If I drop a feather and a elephant from an equal height in a vacuum which will hit the ground first?

Answer 1

Whichever one you drop first will hit the ground first.  If you drop them simultaneously, and they don't interfere with each other on the way down, then they will hit the ground simultaneously.

Answer 2

They will both hit the ground at the same time, as there is no air resistance in a vacuum, and weight does not determine which object will fall faster even where there is gravity.