NCERT Mathematics Class 9 Exemplar Ch 14 Statistics and Probability Part 11

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Q.16. A company selected 4000 households at random and surveyed them to find out a relationship between income level and the number of television sets in a home. The information so obtained is listed in the following table:

A company selected 4000 households at random and surveyed them to find out a relationship between income level and the number of television sets in a home

Monthly income Number of Televisions/household (in Rs)

Number of Televisions/household

0

1

2

Above 2

Find the probability:

(i) Of a household earning per year and having exactly one television.

(ii) Of a household earning and more per year and owning 2 televisions.

(iii) Of a household not having any television.

Answer: (i) (ii) (iii)

Q.17. Two dice are thrown simultaneously 500 times. Each time the sum of two numbers appearing on their tops is noted and recorded as given in the following table:

Two dice are thrown simultaneously 500 times. Each time the sum of two numbers appearing on their tops is noted

Sum

Frequency

2

14

3

30

4

42

5

55

6

72

7

75

8

70

9

53

10

46

11

28

12

15

If the dice are thrown once more, what is the probability of getting a sum?

(i) 3?

(ii) More than 10?

(iii) Less than or equal to 5?

(iv) Between 8 and 12?

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