You are the production manager for a manufacturing firm that produces cell phones. You know the following facts:

• 25% of your daily output is produced by factoryA. 50% of this output is produced during the
• day shift (8:00am - 4:00pm) and 50% is produced during the afternoon shift (4:00pm to 12:00am). 2% of the day shift's output is defective, and 2% of the afternoon shift's output is defective.
• 35% of your daily output is produced by factoryB. 60% of this output is produced during the day shift (8:00am - 4:00pm) and 40% is produced during the afternoon shift (4:00pm to 12:00am). 3% of the day shift's output is defective, while 1% of the afternoon shift's output is defective.
• 40% of your daily output is produced by factoryC. 40% of this output is produced during the day shift (8:00am - 4:00pm) and 60% is produced during the afternoon shift (4:00pm to 12:00am). 2% of the day shift's output is defective, while 3% of the afternoon shift's output is defective.

1. (a)What is the probability that one phone selected at random from the firm's production is not defective?
2. (b)If you select one phone at random and it is defective, what is the probability that it was produced by factory A?