Twenty of the 50 digital video recorders​ (DVRs) in an inventory are known to be defective. What is the probability you randomly select an item that is not​ defective?

1 Answer
Salamander · Martin C.
May 31, 2018

35

Explanation:

Remember that odds for plus odds against must be 1. Therefore, 20 out of 50 of the DVRs are defective, so 30 out of 50 would work. 3050 simplifies into 35, so that would be the probability of you picking out a DVR that works, and the probability of picking one that does not work would be the leftover 25 . Or, if you're answering with a percent, you would have a 60% chance of picking a working DVR.

I hope this helps, I know the explanation isn't really clear, but I can't really think of another way to explain it.

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