A company has two plans to manufacture scooters. Plant I manufactures 80 percent of the scooters and plant II manufactures 20 percent. At plant 1, 85 out of 100 scooters are rated standard quality or better. At plant II, only 65 out of 100 scooters are rated stanard quality or better. What is the probability that scooter selected at random came from plant 1, if it is known that the scooter is of standard quality?