Company A produces 60%of the total output and Company B produces the rest(40%). 5% of the goods for Company A and 10% for company B are defects.

If a good is randomly selected what is the chance of it being a defect.

I have P(Defect)= P(Defect A) + P(Defect B)

If a good is known to be a defect what is the probability it was produced by Company A.

This one I am stuck on, any help would be appreciated