Answer:
The package velocity with respect to the ground is -7 m/s, if we treat helicopter velocity direction as positive.
Explanation:
Velocity of the package relative to the ground is the sum of velocity vector of the package relative to the helicopter and the velocity vector of the helicopter relative to the ground.
Since these 2 vector are in opposite direction, we will pick the package velocity with respect to helicopter negative
= 6 fwd + 13 bwd = 6 fwd + (-13) fwd = -7 fwd or 7 bwd
So the package velocity with respect to the ground is -7 m/s, if we treat helicopter velocity direction as positive.