Airplane A takes off and ascends at a rate of 3000 ft/min. At the same time, Airplane B, which is flying at 30,000 ft, begins to descend at a rate of 2500 ft/min.


Let h represent the height off the ground in feet, and let t represent time in minutes.


Which system models this situation?


A.

h = 3000t

h = 2500 + 30,000t


B.

h = 30,000 + 3000t

h = 30,000 − 3000t


C.

h = 2500t

h = 30,000 − 3000t


D.

h = 3000t

h = 30,000 − 2500t