Robert stands atop a 1,380-foot hill. He climbs down, reaching the bottom of the hill in 30 minutes. What is Robert’s average rate of elevation change in feet per minute?
A. +460.
B. +46
C.-46
D. -460
This is an equation of elevation change. Since it takes 30 minutes do go down 1380 feet, or undergo an elevation change of -1380 feet, the answer is -1380/30, or an average elevation change of -46 feet per minute
