Answer:
2684 m
Step-by-step explanation:
First of all, we should find the time that the survival kit takes to reach the ground. For this purpose, we can only consider the vertical motion of the kit, which is an accelerated motion with constant acceleration g=9.8 m/s^2 (toward the ground) and initial vertical velocity of zero. The vertical distance travelled is S=1800.0 m, so we can find the time by using:

And now we can find the horizontal distance travelled by the kit during this time interval, which corresponds to the distance at which Alex should drop the supplies. The horizontal motion is a uniform motion with constant speed v = 140.0 m/s, so the horizontal distance is
