Since the rate of the rising hot air balloon is 4 meters per second, it will be at a certain distance

after t seconds. On the other hand, a descending parachutist travels a distance of

where t is also in seconds. They will both be at a certain disrance y when they have traveled a common time t. Writing this in systems of equation we'll get:

Then we can solve the system by equating both equations.


ANSWER: The hot air balloon and the parachutist will be at the same height after 20 seconds.