NCERT Class 9 Solutions: Probability (Chapter 15) Exercise 15.1-Part 5 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Define Probability with Equation

Q-12 A study was conducted to find out the concentration of sulphur dioxide in the air parts per million (ppm) of a certain city. The data obtained for 30 days is as follows:

Using this table, find the probability of the concentration of sulphur dioxide in the interval on any of these days.


Total numbers of day՚s data recorded

Numbers of days in which sulphur dioxide in the interval

Required probability

Q-13 The blood groups of students of class VIII are recorded as follows:

A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O, A, AB, O, A, A, O, O, AB, B, A, O, B, A, B, O.

Using this table to determine the probability that a student of this class, selected at random, has blood group AB.


Total numbers of students

Numbers of students having blood group AB

Required probability