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Answer :
Numbers of pens = Numbers of defective pens + Numbers of good pens
\(\therefore \) Total number of pens = 132 + 12 = 144 pens
\( P(E) \ = \ \frac{Number \ of \ favourable \ outcomes}{Total \ number \ of \ outcomes} \)
P(picking a good pen) \( = \ \frac{132}{144} \ = \ \frac{11}{12} \ = \ 0.916 \)