# 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

**Solution:**

We use the basic formula of probability to solve the question given.

Number of defective pens = 12

Number of good pens = 132

Total number of pens = 12 + 132

= 144

The probability that the pen that is taken out is a good one = Number of possible outcomes/Total number of favorable outcomes

= 132/144

= 11/12

Thus, the probability that the pen taken out is a good pen, is 11/12.

**☛ Check: **NCERT Solutions for Class 10 Maths Chapter 15

**Video Solution:**

## 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.

NCERT Solutions for Class 10 Maths Chapter 15 Exercise 15.1 Question 16

**Summary:**

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. If one pen is taken out at random from this lot, the probability that the pen taken out is a good one is 11/12.

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