Solution of problem N3761 probability theory total prob

3761. The assembly shop received parts from 3 workshops of the enterprise: 25 parts from workshop No. 1, 35 from workshop No. 2, 40 from workshop No. 3. The probability of high-quality manufacturing of parts in workshop No. 1 is 0.9, in workshop No. 2 — 0.8, in workshop No. 3 — 0.7. What is the probability that the selected product will be of high quality at random?