(Q14) 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.

Answer :

Number of good pens =

Number of defective pens =

Total number of pens =

∴ Total number of outcomes in taking a pen at random = .

No. of favourable outcomes in taking a good pen = .