Question

An air traffic controller is tracking two planes. To start, Plane A is at an altitude of 3427 feet and Plane B is at an altitude of 5000 feet. Plane A is gaining altitude at 65.75 feet per second and Plane B is gaining altitude at 35.5 feet per second.
How many seconds will pass before the planes are at the same altitude?

What will their altitude be when they're at the same altitude.

Answer 1

3427 + 65.75s = 5000 + 35.5s
65.75s - 35.5s = 5000 - 3427
30.25s = 1573
s = 1573 / 30.25
s = 52 seconds <== they are the same at 52 seconds

3427 + 65.75(52) = 6846
5000 + 35.5(52) = 6846

and their altitude is 6846 <===

Answer 2

lane A, 5000+40.5x
Plane B, 4467+50.75x
x is number of seconds of time. 


When altitudes equal?
5000+40+1/2x=4467+50+.75x
5000-4467=10.25x

x=53.3 seconds.
Use either formula for altitude of a plane to find what the altitude would be.