A car's GPS device is manufactured by only 3 companies: AirGPS, BigGPS, and CharterGPS - who make 8000, 1500, and 500 of all the GPS devices made, respectively. Some of these are defective. Assuming the percentage of defective GPS devices made by AirGPS, BigGPS, and CharterGPS are 4%, 6%, and 9%, respectively. Find the probability that a randomly selected GPS device from all GPS devices that are found to be defective came from AirGPS