An air traffic controller is monitoring the altitudes of four planes. The four equations below show y, the
distance in feet of each plane above the ground, after 6 minutes of descent. (Hint: Look at the slopes to help
you.)
Plane A: y = 400t + 12,000
Plane B: y = -800t + 28,000
Plane C: y = -200t +13,500
Plane D: y = -500t + 30,000
a. Which plane is descending at the slowest rate?
b. Which plane began its descent from the highest altitude?