Answer:
0.3302 or 33.02%
Step-by-step explanation:
Expected defective from A = 0.05 x 350 = 17.5 defective refrigerators.
Expected defective from B = 0.03 x 250 = 7.5 defective refrigerators.
Expected defective from C = 0.07 x 400 = 28 defective refrigerators.
The probability of a refrigerator being produced at plant A, given that it is defective, is determined by dividing the expected number of defective refrigerators from plant A by the expected number of defective refrigerators from all plants:
[tex]P = \frac{17.5}{17.5+7.5+28}\\ P=0.3302 = 33.02\%[/tex]
The probability it was produced at plant A is 0.3302 or 33.02%.