50%, 30% and 20% of the products from company A, B, C respectively are
brought in. The defective rate of the products from the 3 companies are 1%,
3% and 3% respectively. 1 defective product has been picked up randomly.
What is the probability that the defective product picked is from company A?
a) .005
b) 0.25
c) 0.3
d) 0.45
anyone?