Question

A company claims its video game players have a defective rate of 4%. What is the probability that you and a friend both receive a defective player?

Answer 1

Since you're looking for the chance that the defective player occurs twice, you need to find the chance your friend receives a defective player given that you also receive one. The chance you receive a defective player is 4%, or 0.04. If you friend also receives a defective player, then the chance of both occurring is 4% of 4%, or 0.04 * 0.04, which equals 0.0016. So the probability that you can a friend both receive a defective player is 0.16%.