Solving problem N3736 Bayesian probability theory

3736. Of the 45 parts of the same type 10 are made on the first automatic machine, 2 of them are non-standard, 15 are on the second, one is non-standard, 20 are on the third, three of them are non-standard. All parts are piled together. Taken at random item was non-standard. Find the probability that it is made on the second machine.