A company manufactures light bulbs of 3 di?erent types (T1, T2 , T3) some of which are defective right from the factory. From experience with the manufacturing process, it is known that the fraction of defective Type 1 bulbs is 0.1; Types 2 and 3 have respective defective fractions of 1/15 and 0.2.
A batch of 200 bulbs were sent to a quality control laboratory for testing: 100 Type 1, 75 Type 2, and 25 Type 3. What is the probability of ?nding a defective bulb?