Solution of problem N3877 probability theory total prob

Solution of problem N3877 probability theory total prob

3877. A batch of parts is made by three workers, with the first worker producing 25% of all parts, the second worker 35%, the third 40%. In the production of the first working defect is 3%, in the production of the second 4%, in the production of the third 2.5%. What is the probability that an item randomly selected for inspection will be defective?

Additional information:

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