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# One carton was selected at random. What is the probability that it has defective bulbs less than 4? Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the following table:

Number of defective bulbs 0 1 2 3 4 5 6 More than 6

Frequency 400 180 48 41 18 8 3 2

**Solution:**

Given, bulbs are packed in cartons each containing 40 bulbs

700 cartons were examined for defective bulbs.

We have to find the __probability__ of selecting a carton that has defective bulbs less than 4.

Probability of an event = Number of trials in which the event has happened / Total number of trials

From the given table,

Number of cartons which has defective bulbs less than 4 = 400 + 180 + 48 + 41 + 18

= 669

So, number of trials in which the event has happened = 669

Total number trails = 700

Probability of selecting a carton which has defective bulbs less than 4 = 669/700

Therefore, the probability that has defective bulb less than 4 is 669/700

**✦ Try This: **Bulbs are packed in cartons each containing 30 bulbs. Six hundred cartons were examined for defective bulbs and the results are given in the following table:

Number of defective bulbs | 0 | 1 | 2 | 3 | 4 | 5 | 6 | More than 6 |

Frequency | 300 | 125 | 38 | 36 | 40 | 28 | 29 | 4 |

One carton was selected at random. What is the probability that it has defective bulbs less than 3?

**☛ Also Check:** NCERT Solutions for Class 9 Maths Chapter 14

**NCERT Exemplar Class 9 Maths Exercise 14.3 Problem 18(iii)**

## One carton was selected at random. What is the probability that it has defective bulbs less than 4? Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the following table: Number of defective bulbs 0 1 2 3 4 5 6 More than 6 Frequency 400 180 48 41 18 8 3 2

**Summary:**

Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the table. One carton was selected at random. The probability that it has defective bulbs less than 4 is 669/700

**☛ Related Questions:**

- Determine the probability that tomorrow’s output will have no defective part? Over the past 200 work . . . .
- Determine the probability that tomorrow’s output will have atleast one defective part? Over the past . . . .
- Determine the probability that tomorrow’s output will have not more than 5 defective parts? Over the . . . .

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