Question

# $12$ 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$.$

Open in App
Solution

## Given that $:$$12$ defective pens are accidentally mixed with $132$ good ones$.$ One pen is taken out at random.Find out the probability that the pen is taken out is a good one$.$ Numbers of pens $=$ Numbers of defective pens $+$ Numbers of good pens∴ Total number of pens $=132+12$ $=144$ pensLet $E$ be the event of getting a good pen$.$$P\left(E\right)=$$\left($Number of favourable outcomes$/$Total number of outcomes$\right)$$P\left(E\right)=$$\frac{132}{144}$ $=\frac{11}{12}$ $=0.916$Hence$,$ the probability that the pen is taken out is a good one is $0.916$

Suggest Corrections
7
Explore more