Determine the rate at which the radius of a spherical balloon is increasing when the diameter of the balloon is 40cm, if it is known that Air is being pumped into the balloon at a rate of 10cm³/min. 2. Brad and Angelina are riding on bikes, separated by 500 meters. Brad starts riding north at a rate of 4m/sec and 6 minutes later Angelina starts riding south at 4m/sec. At what rate the distance