Question

A diver begins at sea level and dives down 200 feet. He ascends at a steady rate of 12 1/3 feet per minute for 4.5 minutes. Which of the following numerical expressions represents the final depth of the diver?

Answer 1

Suppose the depth of the diver is d at time time t, rate is given by r=12 1/3 ft/ min. The equation representing the depth of the diver at time t will be:
f(t)=200-(12 1/3)t
Therefore the depth of the diver after t=4.5 min will be:
f(4.5)=200-(12 1/3)*4.5
f(4.5)=200-55.5
f(4.5)=144.5 ft
This means that after 4.5 minutes the diver will be 144.5 ft deep.