As a probe descends to the Kuril Trench in the Pacific Ocean, it records the amount of dissolved oxygen in
the water in units of parts per million (ppm). At
depths below 2,000 meters, the dissolved oxygen
drops at a constant rate of d ppm for every change in
depth of 100 meters, until it reaches zero. At a depth
of 2,530 meters, the dissolved oxygen is measured to
be 205 ppm. At a depth of 3,030 meters, the dissolved
oxygen is measured to be 65 ppm. What is the value of
d?