Once his parachute is open, a skydiver descends at a rate of 25 feet per second. 90 seconds after the parachute opens, his altitude is 2750 feet. a) Determine an equation to model the skydiver’s altitude (A) after his parachute has been open for t seconds. b) Use your equation to determine the skydiver’s altitude after the parachute has been open for 2 minutes. c) Once the parachute is open, how long does the skydiver take to reach the ground?