Fifteen of the 100 digital video recorders (DVRs) in an inventory are known to be defective. What is the probability you randomly select a DVR that is not defective? The probability is nothing.

17/20

Step-by-step explanation:

Fifteen of the 100 digital video recorders (DVRs) in an inventory are known to be defective, the total number of non-defective DVRs will be 100-15 = 85 DVRs.

If 85 DVRs are not defective, the probability that you randomly select a DVR that is not defective can be expressed as:

P (non-defective DVRs) = Total number of non-defective DVRs / Total DVRs

P (non-defective DVRs) = 85/100

P (non-defective DVRs) = 17/20

0.85

Step-by-step explanation:

Given;

Number of defective DVRs D = 15

Total number of DVRs T = 100

Number of non defective DVR N = T - D = 100 - 15 = 85

The probability of selecting a non defective DVR P (N) is equal to the number of non defective DVR divided by the total number of DVRs.

P (N) = N/T

Substituting the values;

P (N) = 85/100

P (N) = 17/20 = 0.85