A lot consists of 144 ball pens of which 20 are defective and the others are good.Rafia 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. The probability that she will buy that pen is
- \(\frac{5}{36}\)
- \(\frac{20}{36}\)
- \(\frac{31}{36}\)
- \(\frac{31}{144}\)
The Correct Option is C
Approach Solution - 1
- The total number of pens in the lot is 144.
- The number of defective pens is 20.
- The number of good pens is calculated by subtracting the defective pens from the total number of pens: \(144 - 20 = 124\).
Approach Solution -2
Given: A lot of 144 ball pens, where 20 are defective and the remaining are good.
Step 1: Understanding the Probability of Selecting a Good Pen
Total pens = 144
Defective pens = 20
Good pens = 144 - 20 = 124
Step 2: Probability Calculation
Probability of selecting a good pen = Number of good pens / Total number of pens
= 124 / 144 = 31 / 36
Final Answer: 31 / 36
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