A rock climber’s elevation above sea level changed −8212 feet in 2 1/4 minutes as she descended. What was the climber’s average change in elevation per minute? Enter your answer as a mixed number, i

A rock climber’s elevation above sea level changed −8212 feet in 2 1/4 minutes as she descended. What was the climber’s average change in elevation per minute? Enter your answer as a mixed number, in simplified form, in the box.