When Will the Package Hit the Ground?

[ATranPV]

Homework Statement

A hot-air balloon is ascending at the rate of 10 m/s at a height of 84 m above the ground when a package is dropped.

Find time it took to hit the ground

Find Final velocity

Homework Equations

The Attempt at a Solution

Initially, I am inclined to use the equation Yf = volt + (1/2)at^2

I know that a=-9.8 m/s^2
Vo = 10m/s
Yf=84m

With four variables and 3 are known, I can find time.

The part I am having trouble with is setting up the equation where time is a function of velocty and position (where as t=something)

Am I even approaching this problem correctly? Any help will be much appreciated.
ATranPV

EDIT: Yes...my algebra sucks...:(

 

[rickz02]

Hint: To solve for t, use the quadratic eaquation.