Answer:
7.74 seconds
Step-by-step explanation:
u = 25 m/s
h = - 100 m
Let it takes time t to hit the ground.
Use second equation of motion
![h = ut-(1)/(2)gt^(2)](https://img.qammunity.org/2020/formulas/physics/high-school/9aw45ttp3dx88a7966h7gvcqvj1c94ew4o.png)
![-100 = 25t-4.9t^(2)](https://img.qammunity.org/2020/formulas/physics/high-school/qm09mp6c36j2r08gf1bp5tewvj67z5exxn.png)
![4.9t^(2)-25t-100=0](https://img.qammunity.org/2020/formulas/physics/high-school/6ontfhgs1r9t08ktbjo27ekou5og3n4xym.png)
![t=(25\pm √(625+4* 4.9* 100))/(2*4.9)](https://img.qammunity.org/2020/formulas/physics/high-school/ulpi4u29u3qm6rzrhp72isre3rm4nn1ytp.png)
![t=(25\pm 50.84)/(9.8)](https://img.qammunity.org/2020/formulas/physics/high-school/q8c6q31ymfbl55ochxjv9axj21zhzspzcg.png)
Take positive sign as time can never be negative.
t = 7.74 s
Thus, the package takes 7.74 seconds to reach the ground.