NCERT Exercise 14.1 - Q16 - Probability
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.
Answer: P(good) = 11/12.
Full step-by-step NCERT solution with diagrams on Something by Zero.