Airplane at 19,200 feet descending at a rate of 40 feet per second. Another airplane takes off and ascends at a rate of 60 feet per second. After how many seconds will the airplanes be at the same height? What is the height

Step-by-step explanation:

Let t = flying time in seconds for each plane

Descending rate = 40 ft/s

Ascending rate = 60 ft/s

Descending height, hd = 19200 - 40t

Ascending height, ha = 60t

Equating hd = ha, therefore:

60t = 19200-40t

60t + 40t = 19200

100t = 19200

t = 19200/100

t = 192 seconds

h = 19200 - 192 (40)

h = 19200 - 7680

= 11,520 ft.