Answer:
Step-by-step explanation:
Each plane has a starting altitude and a fixed rate of climb. Its altitude at some time t will be the sum of the starting altitude and t times the rate of climb.
__
plane A
altitude = starting altitude + t × rate of climb
a(t) = 4000 +35.25t
plane B
b(t) = 2427 +65.5t
same altitude
The planes will be at the same altitude at the same time when ...
a(t) = b(t)
4000 +35.25t = 2427 +65.5t
1573 = 30.25t . . . . . . . . . . subtract 2427+35.25t
52 = t . . . . . . . . . . . . . divide by 30.25
That altitude is ...
a(52) = 4000 +35.25×52 = 4000 +1833 = 5833
summary
52 seconds will pass before the planes are at the same altitude.
Their altitude then will be 5833 feet.
