Решение задачи N2975 теория вероятностей

2975. In the two boxes are the details. In the first box there are 10 parts (3 of them are standard), in the second - 15 (of which 6 are standard). One piece is removed from each box at random. Find the probability that both parts will be standard. Find the probability that at random the extracted part from the randomly taken box will be standard.

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