Ex 7.1 Class 9 Maths Ganita Manjari Solutions | Sid Classes
Welcome to Sid Classes, your trusted destination for comprehensive academic resources! In this detailed study guide, we present complete, step-by-step solutions for the NCERT Class 9 Maths Ganita Manjari Chapter 7 Statistics and Probability. Designed to reflect how top-scoring students write their solutions and reasoning in school examinations, this walkthrough makes probability concepts, event likelihoods, and real-world chance evaluations entirely clear.
🔑 Key Probability Concepts Used in this Chapter:
- Probability Scale: Probability ranges from \(0\) (Impossible) to \(1\) (Certain).
- Impossible Event (\(P = 0\)): An event that can never happen under any circumstances.
- Less Likely / More Likely: Events with probabilities closer to \(0\) (less than \(0.5\)) or closer to \(1\) (greater than \(0.5\)).
- Equally Likely (Even Chance): An event with a probability of exactly \(\frac{1}{2}\) or \(0.5\).
- Certain Event (\(P = 1\)): An event that is bound to happen without fail.
NCERT Class 9 Maths Ganita Manjari Chapter 7 Exercise 7.1 Solutions
Question 1
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.
Solution:
(i) The next Monday will come after Sunday.
Ranking & Label: \(1\) (Certain).
Reason: The days of the week follow a fixed, repetitive cyclic order where Monday invariably follows Sunday. Therefore, this event is bound to happen without exception.
(ii) It will snow in Mumbai in July.
Ranking & Label: \(0\) (Impossible).
Reason: Mumbai has a tropical climate with warm temperatures throughout the year, making snowfall geographically and meteorologically impossible.
(iii) An elephant will walk through your classroom today.
Ranking & Label: Close to \(0\) (Impossible / Extremely less likely).
Reason: Wild or domestic large animals like elephants are not kept inside school classrooms, making this event practically impossible during normal school hours.
(iv) You will greet at least one friend at school tomorrow.
Ranking & Label: Close to \(1\) (More likely / Certain).
Reason: Going to school involves interacting with peers, classmates, and friends daily, making greeting a friend highly probable.
Frequently Asked Questions (FAQs)
Q1: What is the range of probability for any event?
A: The probability of any event always lies between \(0\) and \(1\) inclusive.
Q2: What does an event with a probability of 0 signify?
A: It signifies an impossible event that can never occur.
Q3: What is an equally likely event?
A: An event where the chances of occurrence and non-occurrence are equal, such as tossing a fair coin.
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