In this case the rubber raft has horizontal and vertical motion.
Considering vertical motion first.
We have displacement , u = Initial velocity, t = time taken, a = acceleration.
In vertical motion
s = 1960 m, u = 0 m/s, a = 9.81
So raft will take 20 seconds to reach ground.
Now considering horizontal motion of raft
u = 109 m/s, t = 20 s, a = 0
So
So shipwreck was 2180 meter far away from the plane when the raft was dropped.