Solving problem N3714 Bayesian probability theory

3714. Two punchers stuffed on different punchers on the same set of punched cards. The probability that the first puncher makes a mistake is 0.05; for the second puncher, this probability is 0.1. An error was found when checking the punched cards. Find the probability that the first puncher made a mistake. (It is assumed that both perforators were intact.)