SOLUTION: There are four batteries, and one of them is defective. Two are to be selected at random for use on a particular day. Find the probability that the second battery selected is not

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Question 1063630: There are four batteries, and one of them is defective. Two are to be
selected at random for use on a particular day. Find the probability that
the second battery selected is not defective, given that the first was not
defective.
Pleasee explain. Thankyou soo much.

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
There are four batteries, and one of them is defective. Two are to be
selected at random for use on a particular day. Find the probability that
the second battery selected is not defective, given that the first was not
defective.
Since we are given that the first battery was not defective, and assuming
the we are sampling without replacement, we reduce the sample space to
three batteries, one of which is defective and two of which are not 
defective.  So the probability of the second one not being defective 
is now 2/3.

Edwin