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प्रश्न
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.
उत्तर
Total number of pens = 12 + 132 = 144
total number of good pens = 132
P (getting a good pen) = `"number of favourable outcomes"/"total number of outcomes"`
= `132/144`
= `11/12`
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