Company A provides a critical manufacturing part 30% of the time, Company B provides the same part 50% of the time and Company C provides the part the rest of the time. There is a 10% chance of the part being defective if provided by Company A, a 30% chance of the part being defective if provided by Company B, and a 70% chance of the part being defective if provided by Company C. 

What is the probability that the part came from Company B and is defective?