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Class 9 Ganita ManjariClass 9 Maths Solutions | 2026–27
Chapter 7: The Mathematics of Maybe: Introduction to ProbabilityPage 159All 1 Questions on This Page

Class 9 Maths Chapter 7 Exercise Set 7.1 Solutions

Complete step-by-step solutions for Class 9 Mathematics Ganita Manjari Chapter 7 Exercise Set 7.1: What Is Probability? (Page 159). Covers ranking events on a scale from 0 (impossible) to 1 (certain) with clear mathematical reasoning.

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Key Concepts for Exercise Set 7.1

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1

Probability

Probability is a type of measurement used to describe how likely or certain an event is to occur.

2

Random Events

A random event is an event whose exact outcome cannot be predicted in advance.

3

Random Experiment

A random experiment is an experiment or trial where the possible outcomes are known, but the actual outcome cannot be predicted beforehand.

4

Probability Scale

Probability is measured on a scale from 0 to 1.

5

Probability Labels

0 → Impossible Less likely → low chance Equally likely / even chance → outcomes have equal likelihood More likely → higher chance 1 → Certain

6

Subjective Probability

Subjective probability is based on available evidence and how a person interprets the present situation when predicting the likelihood of an event.

Question 1
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Rank the following events on a scale from 0 (Impossible) to 1 (Certain). Label each event: Impossible, less likely, equally likely (even chance), more likely, certain. Give reasons why you gave each event its ranking.

  • (i)The next Monday will come after Sunday.
  • (ii)It will snow in Mumbai in July.
  • (iii)An elephant will walk through your classroom today.
  • (iv)You will greet at least one friend at school tomorrow.
Solution

We rank each event according to how likely it is to occur.

(i) The next Monday will come after Sunday.
Rating:Certain

Every Monday comes after Sunday.

Therefore,
P = 1
(ii) It will snow in Mumbai in July.
Rating:Impossible

In the context of this question, snowfall in Mumbai in July is treated as an impossible event.

Therefore,
P = 0
(iii) An elephant will walk through your classroom today.
Rating:Impossible

An elephant cannot normally walk through a classroom.

Therefore,
P = 0
(iv) You will greet at least one friend at school tomorrow.
Rating:More likely

It is quite likely that you will meet and greet at least one friend at school tomorrow, although it is not certain.

Therefore,

the probability is between 1/2 and 1.

Hence, the ranking is:
(i)Certain
(ii)Impossible
(iii)Impossible
(iv)More likely
Answer:(i) Certain | (ii) Impossible | (iii) Impossible | (iv) More likely

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