Question

An airplane is preparing to land at an airport. It is 42,000 feet above the ground and is descending at the rate of 3,300 feet per minute. At the same​ airport, another airplane is taking off and will ascend at the rate of 2,700 feet per minute. When will the two airplanes be at the same altitude and what will that altitude​ be?

Answer 1

7 minutes

Explanation:

From the question :

Descent = ascent

Initial height * descent rate = initial position * ascent rate

Plane on ground is at an initial position or height of 0

42000 - 3300t = 0 + 2700t

Where, t = time

-3300t - 2700t = 0 - 42000

-6000t = - 42000

t = 42000 / 6000

t = 7 minutes