Scooter factory runs three assembly lines, A, B, and C. 98.9% of line A's scooters pass inspection, while only 97.8% of line B's scooters and 98.5% of line C's scooters pass inspection. If 38% of the factory's scooters come off of assembly line A and 34% come off of assembly line B:
a) what is the probability that a randomly selected scooter passed inspection?
b) what is the probability that if a randomly selected scooter did not pass inspection, it came from assembly line B?