A lot consists of 144 ball pens of which 20 are defective and the others are good. Nuri will buy a pen if it is good, but will not buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that (i) She will buy it? (ii) She will not buy it?
31/36
5/36
Explanation
This problem applies the formula for theoretical probability: P(E) = (Number of favorable outcomes) / (Total number of possible outcomes). The context provides the total number of pens and the number of defective ones. Similar to Example 12 and Question 16 in the provided text, the solution involves identifying the favorable outcomes for each event: 'buying' corresponds to drawing a good pen, while 'not buying' corresponds to drawing a defective pen.