3932. There are three factories producing the same products. At the same time, the 1st plant produces 25%, the 2nd plant - 35%, and the 3rd plant - 40% of all products produced. Marriage is 5% of the products of the 1st plant, 3% of the products of the 2nd and 4% of the products of the 3rd plant. All products are mixed and marketed. Find: a) the probability of buying a defective product; b) the conditional probability that the purchased product is manufactured by the 1st plant, if this product is defective.

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