If the ship started out at -75M and descended to -105M, it traveled 30M. If it then went from -105M to -80M, it traveled 25M vertically. Therefore, the total vertical distance traveled, regardless of direction, was 30 + 25 = 55 meters.
If the kangaroo jumps at 40 km/h, then to travel 2km it would require 2/40 = 1/20 = 0.05 hours. 60*0.05 = 3 minutes. So it would take the kangaroo 3 minutes to go 2 km.
