3825. Casting in blanks comes from two processing shops: 45% from the first shop, 55% from the second shop. Casting of the first workshop has 5% of marriage, the second 15% of marriage. Taken at random, the disc turned out to be without defect. What is the probability of its manufacture the first shop?

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