Question

Question 12 Concentration of SO2 (in ppm) Number of days (frequency )
0.00 − 0.04 4
0.04 − 0.08 9
0.08 − 0.12 9
0.12 − 0.16 2
0.16 − 0.20 4
0.20 − 0.24 2
Total 30

The above frequency distribution table represents the concentration of sulphur dioxide in the air in
parts per million of a certain city for 30 days. Using this table, find the probability of the
concentration of sulphur dioxide in the interval 0.12 − 0.16 on any of these days.

Class 9 - Math - Probability Page 285

Answer 1

Hi friend..

Total number of days =30

Concentration of sulphur dioxide in 0.12--0.16

on any day==2

♀♀♀♀Required probability =2/30=1/15

Hope it is helpful..

Answer 2

Probability is the study of the chances of events happening.

Event:

A Possible outcome or combination of outcomes is called event.

The probability of happening our event always lies from 0 to 1.

The sum of all the probabilities of all possible outcomes of an experiment is 1.

 

Required probability=number of trials in which the event E has happened/Total number of trials

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Solution:

Total numbers of days data to prepare sulphur dioxide  = 30 days

Numbers of days in which sulphur dioxide in the interval 0.12-0.16 = 2

Required probability,P( SO2 in the interval 0.12-0.16) = 2/30 = 1/15

P(SO2 in the interval 0.12-0.16)= 1/15

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Hope this will help you...