Elevator speed = 30 m/s
my jump speed = 5 m/s
Since the Elevator and Jumping action are of opposite direction, the speed should be subtracted to arrive at the right speed.
Actual speed = (Elevator speed - My Jump Speed)
= ( 30 - 5 ) m/s
= 25 m/s
So at the speed of 25 m/s I would hit the ground.