Solving problem N3696 Bayesian probability theory

3696. Two automatic machines make parts which arrive on the general conveyor. The probability of obtaining a non-standard part on the first machine is 0.04, on the second - 0.06. The performance of the first machine is three times greater than the second. a) Find the probability that a piece taken from the conveyor is non-standard at random. b) The part taken from the conveyor turned out to be non-standard. Find the probability that it is made on the first machine.