3984. The store has refrigerators produced by two plants in a 2: 9 ratio. The probability of failure during the warranty period of the refrigerator produced by the first plant is 0.005, and the second is 0.009. The refrigerator bought in the store has sustained the warranty period. Calculate the probability that this refrigerator is produced by a second plant.
Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)