Solution of problem N3983 probability theory total prob

Solution of problem N3983 probability theory total prob

3983. The store received refrigerators produced by two plants. Among them, 80% are manufactured by the 1st plant, and the rest - the second. It is known that 2% of refrigerators of the 1st plant and 3% of refrigerators of the 2nd plant do not meet the standard. What is the probability that a refrigerator taken at random will be standard?

Additional information:

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