Solution of problem N3623 probability theory total prob

3623. In the workshop, three types of automatic machines produce the same parts. Their productivity is the same, but the quality of work is different: the machines of the first type produce 90% of the products of excellent quality, the second - 85% and the third - 80%. All parts made for the change go to the warehouse in one container. Determine the probability that at random the selected part will be of the highest quality if the machines of the first type have 10 pieces, the second - 6, and the third - 4.