Adiver descended 38.27 feet in 8.9 minutes. what was the divers average change in elevation per minute

Average rate of change  =  (amount of change)  /  (time for the change)

                                   =        (-38.27 ft)   /   (8.9 minutes)

                                   =      (-38.27 / 8.9)  (feet/minute)

                                   =          - 4.3 feet per minute