Solving problem N3822 Bayesian probability theory

Solving problem N3822 Bayesian probability theory

3822. Casting in blanks comes from two preparation shops: 75% from the first and 25% from the second. At the same time, the material of the first workshop has 15% of defects, and the second - 20%. Taken at random, the disc was standard. Find the probability that it was made the first shop.

Additional information:

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)