There are four boxes for details.
The probability of the event that details of a specific type are in the first, second, third, or fourth box is 0.6, 0.7, 0.8, and 0.9, respectively.
Find the probability that these details are located in no more than 3 boxes.
A situation the details are in no more than 3 boxes means that they are not in any of the boxes at all, or they can only be in any one, any two, or any three boxes.
Therefore, only one possibility is excluded, when the details are in all four boxes.
Therefore, the desired probability is 1 - 0.6 × 0.7 × 0.8 × 0.9 = 0.6976
Answer: the probability that these details are located in no more than 3 boxes is 0.6976
Next probability problem solution: Calculate the probability of the event: a randomly selected lamp is produced in the first factory