12 defective pens are accidentally mixed with 132 good ones. It is not possible to just look at a pen and tell whether or not it is defective. One pen is taken out at random from this lot. Determine the probability that the pen taken out is a good one.

Explanation

Total no. of pens is `144 (132` good and `12` defective ones)

No. of good ones is `132`
Therefore, `132 `times out `144` a good pen is taken out.


Let E be the event of taking a pen out.

We know that, Probability P(E)` =`

(Total no.of possible outcomes)`div`
(No.of favorable outcomes)
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