Question

A hot-air balloon is 1000 feet off the ground and its altitude is slowly changing at a constant rate of negative 4 1 half feet per second.

How many seconds, s, will it take for the balloon to drop to below 215 feet?

Answer 1

final altitude = initial altitude + (rate of change x time)

Let's call the time it takes for the balloon to drop to below 215 feet "t". We know the initial altitude is 1000 feet and the rate of change is -4.5 feet per second. We want to find t when the final altitude is 215 feet.

215 = 1000 + (-4.5)t

Subtracting 1000 from both sides:

-785 = (-4.5)t

Dividing both sides by -4.5:

t = 175 seconds

Therefore, it will take 175 seconds for the balloon to drop to below 215 feet.

Explanation: