Question

Thirteen of the 100 digital recorders in an inventory are known to be defective. What is the probability you randomly select an item that is not defective?

Answer 1

Subtract 13 from 100. That should give you 87. Divide that by 100. Since it doesn't reduce down, the answer should be 87/100.

This is all assuming that you're only selecting ONE recorder and will put the recorder back once finished selecting it.