NCERT Mathematics Class 9 Exemplar Ch 14 Statistics and Probability Part 12 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q. 18. 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:

Bulbs Are Packed in Cartons Each Containing 40 Bulbs
Number of defective bulbs0123456more than 6
Frequency400180484118832

One carton was selected at random. What is the probability that it has?

(i) No defective bulb?

(ii) Defective bulbs from 2 to 6?

(iii) Defective bulbs less than 4?

Answer: (i) (ii) (iii)

Q. 19. Over the past 200 working days, the number of defective parts produced by a machine is given in the following table:

Over the Past 200 Working Days, the Number of Defective Parts Produced by a Machine
Number of defective parts012345678910111213
Days50322218121210101086622

Determine the probability that tomorrow՚s output will have

(i) No defective part

(ii) At least one defective part

(iii) Not more than 5 defective parts

(iv) More than 13 defective parts

Answer: (i) (ii) (iii) (iv)

Q. 20. A recent survey found that the ages of workers in a factory is distributed as follows:

A Recent Survey Found That the Ages of Workers in a Factory is Distributed
Age (in years)20 - 2930 - 3940 - 4950 - 5960 and above
Number of workers382786463

If a person is selected at random, find the probability that the person is:

(i) 40 years or more

(ii) Under 40 years

Answer: (i) (ii) (iii) (iv)

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