Solution of problem N3934 probability theory total prob

3934. Watches of the same brand are made in three factories and arrive at the store. The first plant produces 20% of all products, the second - 30%, the third - 50%. In the production of the first plant, 5% of all hours are in a hurry, the second - 3%, the third - 2%. What is the probability that the watches bought in the store are in a hurry?