3827. Casting in blanks comes from two shops: 60% from the first shop and 40% from the second. Casting of the first workshop has 5% of the marriage, the second - 10% of the marriage. Taken at random, the disc turned out to be without defect. What is the probability that it is made by the first shop?

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)