Solution of problem N4104 probability theory total prob

Solution of problem N4104 probability theory total prob

4104. Of the 1000 lamps, 810 belong to the 1st installment, 70 to the second, and the rest to the third. In the first batch of 10%, in the second 1%, in the third 2% of defective lamps. One lamp is selected at random. Determine the probability that the selected lamp is defective.

Additional information:

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